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NAUTICAL  CHARTS 


BY 

G.  R.  PUTNAM,  M.S. 

MEMBER    OF    THE    AMERICAN    SOCIETY    OF    CIVIL    ENGINEERS 

DIRECTOR    OF    COAST   SURVEYS,    PHILIPPINE 

ISLANDS,    1900    TO    1906 


FIEST  EDITION 

FIRST    THOUSAND 


NEW  YORK 

JOHN    WILEY  &    SONS 

LONDON:    CHAPMAN   &  HALL,  LIMITED 

1908 


.  D«pt. 


COPYRIGHT,    1908, 
BY 

G.  R.  PUTNAM 


Stanhope  ]prces 

F.    H.   GILSON     COMPANY 
BOSTON.     U.S.A. 


PREFACE 


IN  preparing  the  material  for  a  lecture  on  Charts  for 
Columbia  University,  the  writer  was  impressed  with  the 
fact  that  although  nautical  charts  are  mentioned  or  dis- 
cussed in  many  publications,  there  was  not  found  any  one 
which  covered  the  general  subject  of  their  origin,  con- 
struction, and  use.  In  the  countries  of  the  world  more 
than  a  million  copies  of  such  charts  are  now  issued 
annually.  A  considerable  portion  of  the  human  race  is 
interested  directly  or  indirectly,  whether  as  mariners 
or  passengers  or  shippers,  in  navigation  upon  the  sea. 
Aside  from  supplying  a  handbook  for  those  who  might 
have  a  general  interest  in  the  subject,  it  was  thought 
that  a  discussion  of  charts  might  lead  to  further  con- 
sideration of  the  principles  governing  their  construction. 

This  paper  has  intentionally  been  made  as  non- 
technical as  seemed  feasible  in  treating  a  somewhat 
technical  subject.  The  writer  is  indebted  to  the  Coast 
and  Geodetic  Survey  for  various  illustrative  material 
from  its  archives,  and  to  a  number  of  authors  for  facts 
or  suggestions.  A  list  is  appended  of  books  and  papers 
which  have  been  freely  consulted,  bearing  on  this  and 
related  subjects. 

G.  R.  P. 

WASHINGTON,  D.C.,  May  24,  1908. 


iii 


387693 


CONTENTS 


PAGE 

LIST  OF  BOOKS  OR  PAPERS  BEARING  ON  NAUTICAL  CHARTS 

AND    RELATED    SUBJECTS vii 

CHARTS  AND  MAPS 1 

COLLECTION  OF  INFORMATION  FOR  CHARTS 31 

PREPARATION  OF  INFORMATION  FOR  CHARTS 67 

PUBLICATION  OF  CHARTS 84 

CORRECTION  OF  CHARTS 97 

READING  AND  USING  CHARTS 112 

USE  OF  CHARTS  IN  NAVIGATION 124 

PUBLICATIONS  SUPPLEMENTING  NAUTICAL  CHARTS 154 

INDEX.  161 


LIST  OF  BOOKS  OR  PAPERS  BEARING   ON    NAUTI- 
CAL CHARTS  AND  RELATED  SUBJECTS 


Periplus,  an  Essay  on  the  Early  History  of  Charts,  and  Sailing 

Directions.     A.  E.  Nordenskiold,  Stockholm,  1897. 
Maps,  their  Uses  and  Construction.     G.  James  Morrison,  London, 

1902. 
Charts  and  Chart  Making.     Lieut.  John  E.  Pillsbury,  U.S.N.,  in 

Proceedings  U.  S.  Naval  Institute,  1884. 
Principal  Facts  relating  to  the  Earth's  Magnetism.     L.  A.  Bauer, 

in   U.   S.   Magnetic  Declination   Tables,   Coast  and   Geodetic 

Survey,  1903. 
Marine  Hydrographic  Surveys  of  the  Coasts  of  the  World.     G.  W. 

Littlehales,  in  Report  of  the  Eighth  International  Geographic 

Congress,  1904. 
Smithsonian  Geographical  Tables.     R.  S.  Woodward,  Washington, 

1906. 
Admiralty  Charts,  Abridged  list  of.     Published  by  J.  D.  Potter, 

London,  1907. 
Military  Topography.     Capt.  C.  B.  Hagadorn,  U.S.A.,  West  Point, 

1907. 

Service  Hydrographique  de  la  Marine,  Paris,  1900. 
A  Manual  of  Conventional  Symbols  in  Use  on  Official  Charts. 

United  States  Hydrographic  Office,  Gustave  Herrle,  1903. 
Hydrographical  Surveying.     Admiral  W.  J.  L.  Wharton,  London, 

1898. 
On  the  Correction  of  Charts,  Light  Lists,  and  Sailing  Directions. 

Published  by  J.  D.  Potter,  London,  1904. 
Notes  Relative  to  the  Use  of  Charts.     D.  B.  Wainwright,  Coast 

and  Geodetic  Survey,  1900. 

vii 


viii  Books  or  Papers  on  Nautical  Charts 

The  Law  relating  to  Charts  and  Sailing  Directions.  H.  Stuart 
Moore,  London,  1904. 

Notes  bearing  on  the  Navigation  of  H.  M.  Ships.  Hydrographic 
Office,  London,  1900. 

The  Relations  of  Harbors  to  Modern  Shipping.  W.  H.  Wheeler, 
in  Engineering  News,  September  6,  1906,  New  York. 

Wrinkles  in  Practical  Navigation.  Capt.  S.  T.  S.  Lecky,  London, 
1899. 

Navigation  and  Compass  Deviations.  Commander  W.  C.  P.  Muir, 
U.S.N.,  Annapolis,  1906. 

The  Practice  of  Navigation.     Henry  Raper,  London,  1898. 

Lehrbuch  der  Navigation.     Reichs-Marine-Amt,  Berlin,  1906. 

The  Nautical -Magazine,  London. 

Dangers  and  Ice  in  the  North  Atlantic  Ocean.  Bureau  of  Naviga- 
tion, U.  S.  Navy  Department,  1868. 

Reported  Dangers  in  the  North  Pacific  Ocean.  U.  S.  Hydro- 
graphic  Office,  1871. 

Pacific  Islands,  Vol.  Ill,  chapter  on  "Vigias."  British  Hydro- 
graphic  Office,  London,  1900. 

Harriman  Alaska  Expedition,  Vol.  II,  Bogoslof,  our  Newest  Vol- 
cano, by  C.  Hart  Merriam,  New  York,  1901. 

Expedition  to  the  Aleutian  Islands,  1907.  T.  A.  Jaggar,  Jr.,  in 
The  Technology  Review,  1907,  Boston. 

Recent  Changes  in  Level  in  the  Yakutat  Bay  Region,  Alaska,  by 
R.  S.  Tarr  and  Lawrence  Martin,  in  Bulletin  of  the  American 
Geological  Society,  1906. 

An  Index  to  the  Islands  of  the  Pacific  Ocean.  W.  T.  Brigham, 
Honolulu,  1900. 

Geography,  articles  by  C.  R.  Markham,  A.  R.  Clarke,  and  H.  R. 
Mill  in  Encyclopaedia  Britannica. 

Development  in  Dimensions  of  vessels,  Elmer  L.  Corthell, 
Tenth  International  Navigation  Congress,  1905. 


NAUTICAL    CHAKTS 


CHARTS   AND    MAPS 

Need  of  maps.  Maps  are  useful  and  necessary  for 
many  purposes.  Only  by  means  of  a  correct  map 
or  globe  can  a  clear  idea  of  the  geography  of  a  region 
be  given.  An  attempt  to  convey  the  same  information 
by  a  written  description  would  in  comparison  be  both 
cumbersome  and  obscure.  Even  by  passing  over  an 
extensive  region  a  man  unaided  by  instruments  will 
obtain  only  a  rather  crude  notion  of  the  relations,  which 
he  could  clearly  see  on  a  good  map.  The  importance 
among  the  human  arts  of  the  making  of  maps  is  indi- 
cated by  the  references  to  them  in  very  early  historical 
records,  and  by  the  skill  in  map  drawing  shown  by 
some  of  the  primitive  peoples  of  to-day.  This  skill 
exists  particularly  among  races  whose  mode  of  life 
gives  them  a  wide  horizon,  as  for  instance  the  Eskimos. 
An  interesting  instance  of  this  was  the  case  of  Joe,  an 
Eskimo  guide,  who,  in  1898,  before  the  surveys  of  the 
Yukon  delta  were  made,  drew  a  map  of  the  Yukon 
mouths  with  much  more  complete  information  than  any 
previously  available. 

Without  attempting  to  enumerate  in  detail  the  special 
uses  for  maps,  in  the  broader  sense  they  may  be  said 
to  be  essential  for  commercial,  engineering,  military, 

scientific,  educational,  and  political  purposes. 

i 


Charts  and  Maps 


Early  geography  and  map  making.  The  oldest  map 
known  is  a  plan  of  gold  mines  in  Nubia,  drawn  on  a 
papyrus.  This  is  of  the  thirteenth  century  B.C.,  and 
was  found  in  Egypt. 

In  the  earliest  historic  times  men  believed  the  earth 
to  be  a  flat  surface  of  nearly  circular  outline,  a  natural 
inference  for  those  with  limited  outlook  and  communi- 
cation. Later  the  idea  was  introduced  of  the  ocean  as 
a  river  bounding  the  earth  disk.  The  spherical  theory 
of  the  earth  was,  however,  early  accepted  by  learned 
men,  and  was  demonstrated  by  Aristotle  (384  to 
322  B.C.),  who  used  as  proofs  the  earth's  shadow  on  the 
moon,  and  the  change  in  the  visibility  of  the  stars  in 
traveling  north  or  south.  Crates  constructed  a  terres- 
trial globe  in  the  second  century  B.C. 

There  is  no  Greek  or  Latin  map  extant  of  earlier 
date  than  the  time  of  Ptolemy,  but  there  are  references 
showing  that  maps  were  in  use.  One  of  the  first  of 
such  passages  in  Greek  literature  is  the  interesting 
comment  of  Herodotus  written  in  the  fifth  century  B.C., 
"  but  I  laugh  when  I  see  many  who  already  have  drawn 
the  circuits  of  the  earth,  without  any  right  understanding 
thereof.  Thus  they  draw  Oceanus  flowing  round  the 
earth,  which  is  circular,  as  though  turned  by  a  lathe, 
and  they  make  Asia  equal  to  Europe." 

A  map  of  the  world  was  drawn  by  Anaximander, 
560  B.C.  A  hundred  years  later  Democritus  drew  a 
map  having  an  oblong  shape,  and  taught  that  the  width 
of  the  world  from  east  to  west  was  one  and  a  half  times 
its  extent  from  north  to  south,  a  conclusion  based  on 
his  travels  eastward  as  far  as  India.  This  theory, 
which  was  for  a  time  accepted,  has  left  an  enduring 


Early  Geography  and  Map  Making  3 

mark  in  the  words  longitude  and  latitude,  originally 
signifying  the  length  and  the  breadth  of  the  earth. 

The  first  application  of  astronomy  to  geography  was 
made  by  Pytheas,  who  about  326  B.C.  obtained  the  lati- 
tude of  Marseilles  by  an  observation  of  the  altitude  of  the 
sun.  Dicearchus  in  310  B.C.  determined  the  first  parallel 
of  latitude  by  noting  places  where  on  the  same  day  the 
sun  cast  shadows  of  equal  length  from  pillars  of  equal 
height.  Eratosthenes  (276  to  196  B.C.)  was  the  first 
to  compute  the  circumference  of  the  earth  from  obser- 
vations of  the  altitude  of  the  sun  at  Alexandria  and  at 
Syene  in  Upper  Egypt  and  an  estimation  of  the  distance 
between  these  two  places.  Ptolemy,  a  Greek  of  Alexan- 
dria, in  the  years  from  127  to  151  A.D.  wrote  extensively 
on  geographic  subjects,  and  collected  into  systematic 
form  all  geographic  knowledge  then  existing;  he  was 
the  greatest  geographer  of  early  history. 

In  the  ten  centuries  which  followed,  part  of  the  early 
advance  in  this  science  was  obscured,  and  the  theory 
that  the  earth  was  a  flat  disk  surrounded  by  the  sea 
again  became  prevalent.  The  voyages  of  discovery 
of  the  middle  ages,  however,  led  to  a  rapid  develop- 
ment of  geographic  knowledge. 

The  flattening  of  the  spherical  earth  was  not  sus- 
pected until  in  1672  a  clock  regulated  to  beat  seconds 
at  Paris,  when  taken  to  Cayenne  near  the  equator  was 
found  to  lose  two  and  one-half  minutes  a  day.  New- 
ton proved  that  this  was  due  to  the  fact  that  the  earth 
is  an  oblate  spheroid.  In  1735  accurate  measurements 
were  undertaken  to  determine  the  size  and  shape  of 
the  earth.  The  equatorial  diameter  has  been  found 
to  be  7926.6  miles  and  the  polar  diameter  7899.6  miles, 


4  Charts  and  Maps 


the  difference,  or  27  statute  miles,  being  the  amount  of 
the  flattening  at  the  poles. 

The  first  sailing  directions.  The  early  Greek  and 
Roman  writers  do  not  allude  to  charts  or  maps  intended 
especially  for  the  use  of  seafarers.  There  are,  however, 
extant  several  peripli  or  descriptions  of  the  coast.  Some 
of  these  appear  certainly  to  have  been  intended  for  use 
as  nautical  guides,  corresponding  to  the  modern  sail- 
ing directions.  It  is  probable  that  they  were  explan- 
atory of  or  accompanied  by  coast  charts,  now  lost. 
They  are  of  interest  therefore  as  being  probably  the  first 
compilations  for  the  guidance  of  seamen.  One  of  the 
earliest,  written  apparently  in  the  fifth  and  fourth 
centuries  B.C.,  is  entitled  "Scylax  of  Caryanda,  his 
circumnavigation  of  the  sea  of  the  inhabited  part  of 
Europe  and  Asia  and  Libya."  It  contains  a  systematic 
description  of  the  coasts  of  the  Mediterranean,  Black 
Sea,  and  part  of  the  west  coast  of  Africa.  The  fol- 
lowing are  some  extracts  which  indicate  the  character 
of  the  work.  It  is  to  be  noted  that  no  bearings  are 
given,  and  that  distances  are  usually  stated  by  day's 
sail;  Africa  is  referred  to  as  Libya. 

"  Europe.  I  shall  begin  from  the  Pillars  of  Hercules 
in  Europe  and  continue  to  the  Pillars  of  Hercules  in 
Libya,  and  as  far  as  the  land  of  the  great  Ethiopians. 
The  Pillars  of  Hercules  are  opposite  each  other,  and  are 
distant  from  each  other  by  one  day's  sail.  .  .  .  From 
Thonis  the  voyage  to  Pharos,  a  desert  island  (good 
harborage  but  no  drinking  water),  is  150  stadia.  In 
Pharos  are  many  harbors.  But  ships  water  at  the 
Marian  mere,  for  it  is  drinkable.  .  .  .  From  Cher- 
sonesus  is  one  day's  sail;  but  from  Naustathmus  to 


The  First  Sailing  Directions 


the  harbor  of  Cyrene,  100  stadia.  But  from  the  harbor 
to  Cyrene,  80  stadia;  for  Cyrene  is  inland.  These 
harbors  are  always  fit  for  putting  into.  And  there  are 
other  refuges  at  little  islands,  and  anchorages  and  many 
beaches,  in  the  district  between.  .  .  .  After  the  isthmus 
is  Carthage,  a  city  of  the  Phoenicians,  and  a  harbor. 
Sailing  along  from  Hermsea  it  is  half  a  day  to  Carthage. 
There  are  islands  off  the  Hermsean  cape,  Pontia  island 
and  Cosyrus.  From  Hermaea  to  Cosyrus  is  a  day's 
sail.  Beyond  the  Hermsean  cape,  towards  the  rising 
sun,  are  three  islands  belonging  to  this  shore,  inhabited 
by  Carthaginians;  the  city  and  harbor  of  Melite,  the 
city  of  Gaulus,  and  Lampas;  this  has  two  or  three 
towers.  .  .  .  The  sailing  along  Libya  from  the  Canopic 
mouth  in  Egypt  to  the  Pillars  of  Hercules  .  .  .  takes 
74  days  if  one  coast  round  the  bays.  .  .  .  From  the 
cape  of  Hermsea  extend  great  reefs,  that  is,  from  Libya 
towards  Europe,  not  rising  above  the  sea;  it  washes 
over  them  at  times.  .  .  .  From  Thymiateria  one  sails 
to  cape  Soloes,  which  juts  far  into  the  sea.  But  all 
this  district  of  Libya  is  very  famous  and  very  sacred.  .  .  . 
This  whole  coasting  from  the  Pillars  of  Hercules  to 
Cerne  Island  takes  twelve  days.  The  parts  beyond  the 
isle  of  Cerne  are  no  longer  navigable  because  of  shoals, 
mud,  and  sea-weed.  This  sea-weed  has  the  width  of 
a  palm,  and  is  sharp  towards  the  points,  so  as  to  prick." 
That  there  were  many  other  similar  writings  in  the 
following  centuries  is  shown  by  the  following  quotation 
from  Marcianus,  in  a  preface  to  sailing  directions 
written  in  the  fifth  century  A.D.*  "This  I  write  after 
having  gone  through  many  sailing  directions,  and  spent 
much  time  on  their  examination.  For  it  behooves  all 


6  Charts  and  Maps 


who  are  men  of  education,  to  scrutinise  such  attempts 
at  learning  in  this  subject,  so  as  neither  rashly  to  believe 
the  things  that  are  said,  nor  incredulously  to  set  their 
private  opinions  against  the  careful  decisions  of  others." 

The  oldest  extant  sailing  directions  of  the  middle 
ages  bear  date  1306  to  1320. 

Development  of  chart  making.  The  application  of 
the  compass  to  nautical  use  in  the  twelfth  century 
A.D.  had  a  marked  effect  in  encouraging  voyages  of 
exploration,  and  therefore  indirectly  on  chart  making. 
The  following,  written  toward  the  close  of  the  twelfth 
century,  is  the  first  known  mention  of  the  use  of  the 
compass  in  Europe:  "The  sailors,  moreover,  as  they  sail 
over  the  sea,  when  in  cloudy  weather  they  cannot  longer 
profit  by  the  light  of  the  sun,  or  when  the,  \vorld  is 
wrapped  in  the  darkness  of  the  shades  of  night,  and 
they  are  ignorant  to  what  part  of  the  horizon  the  prow 
is  directed,  place  the  needle  over  the  magnet,  which 
is  whirled  round  in  a  circle,  until,  when  the  motion 
ceases,  the  point  of  it  (the  needle)  looks  to  the  north." 
The  nautical  compass  of  that  time  appears  to  have 
consisted  of  a  magnetized  needle,  floated  in  a  vessel 
of  water  by  a  cork  or  reed,  and  having  no  index 
nor  compass  card.  Peregrinus  in  1269  made  notable 
improvements  in  the  compass,  including  a  pivot  sus- 
pension for  the  needle,  a  graduation,  a  lubber  line, 
and  an  azimuth  bar  for  sighting  on  the  sun  or  other 
object. 

Nautical  charts  are  known  to  have  been  in  use  since 
the  thirteenth  century  A.D.,  but  the  earliest  extant  of 
which  the  date  can  be  fixed  is  Vesconte's  loxodromic 
chart  of  1311. 


Development  of  Chart  Making 


The  loxodromic  charts  first  appeared  in  Italy,  and 
were  so  called  from  the  fact  that  they  were  crossed  by 
loxodromes  (or  rhumb  lines)  radiating  from  a  number 
of  crossing  points  distributed  regularly  over  the  map. 
Compass  roses  carefully  drawn  were  later  added  at  these 
crossing  points,  the  first  appearing  on  a  chart  of  1375. 
The  earliest  known  mention  of  the  variation  of  the 
compass  from  true  north  was  on  the  first  voyage  of 
Columbus,  who  discovered  this  important  fact  in  1492, 
and  as  a  consequence  his  "seamen  were  terrified  and 
dismayed."  Before  that  time  it  was  assumed  in  Europe 
that  the  compass  pointed  "true  to  the  north  pole." 
The  apparent  failure  to  detect  the  variation  earlier  was 
doubtless  to  som.e  extent  due  to  its  small  amount  at 
that  time  along  the  Mediterranean.  The  earlier  charts 
showed  both  lines  and  compass  roses  apparently 
oriented  with  the  true  meridian,  though  there  is  some 
evidence  to  indicate  that  they  were  actually  oriented 
with  the  magnetic  meridian,  the  designer  not  recognizing 
any  difference.  The  variation  of  the  compass  was  first 
marked  on  a  map  in  1532  and  on  a  printed  chart  in 
1595,  but  the  placing  of  magnetic  compasses  on  charts 
did  not  become  customary  until  about  fifty  years  ago. 
These  early  charts  were  drawn  on  parchment,  using 
bright  colors.  They  were  copied  by  hand,  one  from 
another,  with  gradual  variations.  They  had  no  pro- 
jections, and  the  draftsmen  evidently  had  no  idea  of 
the  sphericity  of  the  earth.  Islands  and  points  were 
usually  exaggerated;  shallows  were  indicated,  but  no 
soundings;  no  information  was  given  as  to  the  interior 
of  the  countries ;  a  scale  of  distances  was  nearly  always 
provided. 


8  Charts  and  Maps 


Charts  were  first  printed  about  1477,  and  are  known 
to  have  been  engraved  on  copper  by  1560. 

The  maps  of  Ptolemy  were  ruled  with  degree  lines, 
but  no  chart  was  so  provided  until  1427;  by  1500, 
however,  most  charts  were  graduated.  Before  this 
date  it  is  not  known  on  what  projection  the  charts 
were  constructed.  On  the  first  graduated  charts  the 
degree  lines  were  equidistant  parallel  straight  lines 
cutting  each  other  at  right  angles  and  thus  dividing 
the  chart  into  equal  squares  or  rectangles.  These 
were  known  as  "  plain  charts."  This  square  projection 
had  little  to  commend  it  save  simplicity  of  construction, 
as  in  higher  latitudes  it  gave  neither  directions  nor 
distances  correctly.  The  difficulties  of  its  use  in  nav- 
igation were  early  recognized,  and  nautical  works  con- 
tained chapters  on  "sailing  by  the  plain  chart,  and  the 
uncertainties  thereof." 

The  example  of  early  chart  making  shown  in  Fig.  2 
is  of  great  interest  as  being  the  earliest  extant  chart 
which  includes  America.  This  chart  was  drawn  on 
ox-hide  in  1500  by  Juan  de  la  Cosa,  who  accompanied 
Columbus  on  his  first  voyage  as  master  of  his  flagship, 
and  on  his  second  voyage  as  cartographer.  The  chart, 
of  which  only  a  portion  is  shown  here,  purports  to 
cover  the  entire  world;  it  joins  Asia  and  America  as  one 
continent,  the  Pacific  Ocean  being  then  still  unknown. 
Gerhard  Kramer,  a  Flemish  map-maker,  better 
known  by  his  Latin  name  of  Mercator,  in  1569  pub- 
lished his  famous  Universal  Map.  In  this  map  the 
meridians  and  parallels  were  still  straight  lines  inter- 
secting at  right  angles,  but  the  distances  between  the 
parallels  were  increased  with  increasing  latitude  in 


FIG.  2.      CHART  OF   NORTH    ATLANTIC   OC  ft 


BY  JUAN    DE    LA   COSA,   1500.      EARLIEST   EXTANT  CHART   SHOWING   AMERICA. 


Development  of  Chart  Making  9 

such  proportion  that  a  rhumb  line,  or  line  cutting  the 
meridians  at  a  constant  angle,  would  appear  on  the 
map  as  a  straight  line.  Mercator  never  explained 
the  construction  of  his  chart,  and  as  the  above  condition 
was  not  accurately  carried  out,  it  is  thought  that  the 
chart  was  drawn  by  comparing  a  terrestrial  globe 
with  a  "plain  chart."  After  examination  of  a  merca- 
tor  chart  in  1590,  Edward  Wright  developed  the  cor- 
rect principles  on  which  such  a  chart  should  be 
constructed,  and  published  in  1599  his  treatise  "The 
Correction  of  Certain  Errors  in  Navigation."  It  took 
nearly  a  century  to  bring  this  chart  into  use,  and  even 
in  the  middle  of  the  eighteenth  century  nautical  writers 
complain  that  "  some  prefer  the  plain  chart." 

The  Arcano  del  Mare,  1646,  was  the  first  marine 
atlas  in  which  all  the  maps  were  drawn  on  the  merca- 
tor  projection. 

In  the  sixteenth,  seventeenth  and  eighteenth  centuries 
charts  and  sailing  directions  were  often  bound  together 
in  large  volumes.  These  usually  had  quaint  titles,  not 
overburdened  with  modesty,  of  which  the  following  is 
an  example:  "The  Lightning  Columne,  or  Sea-Mirrour, 
containing  the  Sea-Coasts  of  the  Northern,  Eastern, 
and  Western  Navigation.  Setting  forth  in  divers 
necessaire  Sea-Cards,  all  the  Ports,  Rivers,  Bayes, 
Roads,  Depths,  and  Sands.  Very  curiously  placed  on 
its  due  Polus  height  furnished.  With  the  Discover- 
ies of  the  chief  Countries  and  on  what  Cours  and  Dis- 
tance they  lay  one  from  another.  Never  there  to  fore 
so  Clearly  laid  open,  and  here  and  there  very  diligently 
bettered  and  augmented  for  the  use  of  all  Seamen. 
As  alsoo  the  situation  of  the  Northerly  Countries,  as 


10  Charts  and  Maps 


Islands,  the  Strate  Davids,  the  Isle  of  Jan  Mayen, 
Bears  Island,  Old  Greenland,  Spitsbergen  and  Nova 
Zembla.  Adorneth  with  many  Sea-Cards  and  Dis- 
coveries. Gathered  out  of  the  Experiences  and  prac- 
tice of  divers  Pilots  and  Lovers  of  the  famous  Art  of 
Navigation.  Where  unto  is  added  a  brief  Instruction 
of  the  Art  of  Navigation,  together  with  New  Tables 
of  the  Sun's  Declination,  with  a  new  Almanach.  At 
Amsterdam.  Printed  by  Casparus  Loots-Man,  Book- 
seller in  the  Loots-Man,  upon  the  Water.  Anno  1697. 
With  Previlege  for  fiftheen  years." 

In  1633  a  cartographer  was  appointed  to  the  States- 
General  of  Holland,  and  it  was  his  duty  to  correct  the 
charts  from  the  ships'  logs.  The  Dutch  at  an  early 
date  made  important  progress  in  publishing  charts. 
In  1720  there  was  established  in  Paris  by  order  of  the 
king,  a  central  chart  office  ("depot  des  cartes  et  plans, 
journaux  et  memoires  concernant  la  navigation  "),  and 
in  1737  the  first  charts  were  published  by  this  office. 
Detailed  surveys  of  the  coast  of  France  were  com- 
menced in  1816. 

In  1740  "  the  commissioners  for  the  discovery  of 
longitude  at  sea"  were  authorized  by  Parliament  to 
expend  money  on  the  survey  of  the  coasts  of  Great 
Britain,  this  commission  having  been  created  in  1713. 
Various  rewards  were  offered  by  this  commission, 
including  one  of  £10,000,  for  the  discovery  of  a  method 
of  determining  the  longitude  within  60  miles,  an  inter- 
esting side  light  on  the  uncertainties  of  navigation  at 
that  time.  Compensated  timepieces,  which  have  been 
so  important  a  factor  in  improving  navigation,  were 
invented  by  Harrison  about  1761. 


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Development  of  Chart  Making  13 

In  1795,  by  an  Order  in  Council,  a  Hydrographical 
Office  was  established  in  London,  "to  take  charge  and 
custody  of  such  plans  and  charts  as  then  were,  or  should 
thereafter  be,  deposited  in  the  Admiralty,  and  to  select 
and  compile  such  information  as  might  appear  to  be 
requisite  for  the  purpose  of  improving  navigation." 
This  office  had  at  first  one  assistant  and  one  draftsman. 
Before  that  time  many  charts  of  a  private  or  semi- 
official character  had  been  published;  the  catalogue  of 
the  East  India  Company  in  1786  included  347  charts. 

In  1807  the  Congress  of  the  United  States  authorized 
the  President  "to  cause  a  survey  to  be  taken  of  the 
coasts  of  the  United  States,  in  which  shall  be  designated 
the  islands  and  shoals,  with  the  roads  or  places  of 
anchorage,  within  twenty  leagues  of  any  part  of  the 
shores  of  the  United  States;  and  also  the  respective 
courses  and  distances  between  the  principal  capes,  or 
headlands,  together  with  such  other  matters  as  he  may 
deem  proper  for  completing  an  accurate  chart  of  every 
part  of  the  coasts  within  the  extent  aforesaid."  This 
law  was  the  origin  of  the  present  United  States  Coast 
and  Geodetic  Survey,  now  under  the  Department  of 
Commerce  and  Labor. 

In  1841  a  systematic  survey  of  the  Great  Lakes  was 
commenced;  this  is  the  Survey  of  the  Northern  and 
Northwestern  Lakes,  briefly  known  as  the  Lake  Survey, 
conducted  under  the  Corps  of  Engineers. 

In  1866  the  United  States  Hydrographic  Office  was 
established  under  the  Navy  Department  "for  the 
improvement  of  the  means  for  navigating  safely  the 
vessels  of  the  Navy,  and  of  the  mercantile  marine,  by 
providing  under  the  authority  of  the  Secretary  of 


14  Charts  and  Maps 


the  Navy,  accurate  and  cheap  nautical  charts,  sailing 
directions,  navigators,  and  manuals  of  instructions  for 
the  use  of  all  vessels  of  the  United  States,  and  for  the 
benefit  and  use  of  navigation  generally." 

Systematic  surveying  and  chart  making  date  back 
little  more  than  a  century,  and  most  of  the  information 
shown  on  modern  charts  has  been  gathered  in  that 
time.  At  present  all  the  principal  maritime  nations  of 
the  world  have  made,  or  are  extending,  careful  surveys 
of  their  own  coasts. 

Several  of  the  countries  have  added  valuable  contri- 
butions in  the  examination  of  other  regions  and  oceanic 
areas  beyond  their  borders.  The  maritime  and  colonial 
interests  of  Great  Britain  impelled  that  nation  to  carry 
on  extensive  surveys  along  coasts  whose  inhabitants 
were  not  prepared  to  do  this  work  in  the  earlier  days; 
the  British  have  made"  surveys  along  the  coasts  of  Asia 
and  Africa  and  a  part  of  South  America,  and  the  result- 
ing charts  have  been  a  very  important  and  not  suffi- 
ciently known  contribution  to  commercial  intercourse 
among  the  nations,  as  well  as  to  geography. 

The  Dutch,  French,  Spanish,  and  other  European 
governments  have  made  nautical  surveys  in  various 
parts  of  the  world,  largely  in  connection  with  their  own 
colonies,  and  in  recent  years  much  useful  work  has 
been  done  by  vessels  of  the  German  government.  The 
United  States  has  also  beyond  its  own  territory  made 
valuable  additions  to  hydrographic  knowledge  in  the 
work  of  officers  of  the  Navy  in  a  number  of  oceanic 
exploring  expeditions,  and  surveys  on  the  coasts  of 
Mexico  and  in  the  West  Indies,  and  in  the  explorations 
of  Fish  Commission  vessels. 


Progress  of  Hydrographic  Surveys  17 

Extension  of  maritime  surveys.  Of  the  total  area  of 
the  earth's  surface,  51,886,000  square  miles  is  land  and 
145,054,000  square  miles  is  sea.  The  oceans  thus 
occupy  nearly  three-fourths  of  the  whole  surface,  afford- 
ing highways  open  to  the  nations.  To  conduct  inter- 
national commerce  by  water  the  ships  of  one  country 
must  enter  the  ports  of  another.  Thus  both  on  the 
open  sea  and  in  the  harbors  there  is  an  interest,  common 
to  seamen  of  all  nationalities,  in  the  advance  of  marine 
surveys  and  in  the  publication  of  charts. 

To  keep  the  coasts  properly  charted,  as  well  as  lighted 
and  buoyed,  is  an  obligation  devolving  on  modern 
nations,  not  only  for  the  benefit  of  their  own  commerce 
but  for  that  of  other  countries. 

As  shown  below,  only  a  small  part  of  the  coast  line 
of  the  world  is  thoroughly  surveyed.  In  the  extensive 
ocean  areas  which  are  dotted  with  islands  or  reefs,  a  large 
amount  of  work  is  required  for  their  sufficient  charting, 
although  many  doubtful  areas  have  been  cleared  up  in 
recent  years.  Even  the  parts  that  are  known  to  be  of 
depths  so  great  as  to  be  free  from  navigational  dangers 
should  be  sounded  over  sufficiently  to  develop  the  gen- 
eral configuration  of  the  ocean  bottom. 

Through  international  understanding  a  thorough 
exploration  of  all  the  water  area  of  the  globe  and  the 
coasts  may  in  time  be  effected,  and  the  many  doubtful 
spots  which  still  disfigure  the  charts  may  be  either 
eliminated  or  definitely  located. 

Present  state  of  progress  of  hydrographic  surveys.  A 
comparatively  small  proportion  of  the  coasts  of  the 
world  can  be  considered  as  completely  surveyed  at  the 
present  time,  and  even  such  regions  require  much 


18  Charts  and  Maps 


additional  revision.  In  the  class  of  more  thoroughly 
surveyed  coasts  should  be  included  the  Atlantic  and 
most  of  the  Pacific  coast  of  the  United  States,  Porto 
Rico,  nearly  all  the  coasts  of  Europe,  Algeria,  and 
portions  of  the  coasts  of  Japan,  the  Philippine  Islands, 
and  India. 

A  large  part  of  the  world's  coasts  has  been  surveyed 
incompletely,  but  sufficiently  well  to  permit  the  publi- 
cation of  navigational  charts.  This  is  the  condition  as 
respects  most  of  southeastern  Alaska  and  some  other 
portions  of  the  Alaskan  coast,  British  Columbia,  most 
of  Mexico,  Central  America,  the  West  Indies,  Brazil 
and  parts  of  Chile,  the  Hawaiian  Islands,  China,  Malay 
Peninsula,  Siam,  the  Dutch  East  Indies,  Australia, 
New  Zealand,  Persia,  Arabia,  most  of  Africa,  Iceland, 
northern  Scandinavia,  and  Finland. 

Another  considerable  portion  of  the  coasts  has  not 
been  surveyed,  but  has  been  covered  by  explorations 
which  have  been  embodied  in  nautical  charts  of  varied 
degrees  of  incompleteness.  In  this  class  are  the  north 
coast  and  considerable  portions  of  the  south  and  west 
coasts  of  Alaska,  the  Aleutian  Islands,  Siberia,  most  of 
the  oceanic  groups  in  the  Pacific,  the  northern  coasts 
of  Europe  and  North  America,  Greenland,  the  west 
coast  of  South  America,  Venezuela,  and  Argentina. 

Only  a  very  small  proportion  of  the  total  length  of 
coasts  is  now  entirely  unexplored,  and  such  portions 
are  confined  to  the  polar  regions. 

Chart  publications  of  various  nations.  There  are 
about  eighteen  nations  publishing  navigational  charts, 
and  adding  to  the  information  on  which  charts  are 
based.  Many  of  these  nations  republish  to  some  extent 


Systems  in  Use  on  Various  Charts  19 

the  charts  prepared  by  the  others.  Great  Britain  has 
kept  up  a  series  of  charts  covering  all  parts  of  the  world 
and  practically  including  in  some  form  all  information 
published  elsewhere.  This  series  now  (1908)  includes 
3725  different  charts,  of  which  the  annual  issue  is 
about  600,000  copies.  France  (1906)  publishes  2948 
different  charts. 

In  the  United  States,  charts  are  published  by  the 
Coast  and  Geodetic  Survey  for  the  coasts  and  tidal 
waters  of  the  main  country  and  the  insular  possessions, 
by  the  Hydrographic  Office  for  oceanic  areas  and  for- 
eign coasts,  and  by  the  Lake  Survey  for  the  Great  Lakes*. 
The  total  number  of  different  charts  issued  by  these 
bureaus  is  about  2300,  and  the  total  annual  issue  is 
about  225,000  copies. 

Systems  in  use  on  various  charts. 

Longitude.  The  first  chart  of  New  York,  published 
by  the  Coast  Survey  in  1844,  was  referred  to  the  City 
Hall  of  New  York  as  the  initial  longitude,  and  some 
years  ago  it  was  the  prevailing  custom  for  each  nation 
to  use  a  local  initial  longitude.  While  this  satisfied 
local  pride  it  led  to  much  geographical  and  naviga- 
tional, confusion.  Happily  the  charts  of  all  countries 
are  now  referred  to  Greenwich,  with  the  following 
exceptions : 

France  refers  to  Paris,  which  is  2°  20'  15"  E.  of  Greenwich. 
Spain  refers  to  San  Fernando,  which  is  6°  12' 20"  W.of  Greenwich. 
Portugal  refers  to  Lisbon,  which  is  9°  08'  24"  W.  of  Greenwich. 

Units  for  depths.  The  English  fathom  or  foot  is  used 
for  depths  on  the  charts  of  Great  Britain,  the  United 
States,  and  Japan.  Russia  uses  the  sajene  of  seven 


20  Charts  and  Maps 


English  feet.  On  the  modern  charts  of  practically  all 
the  other  countries  the  meter  is  used,  though  on  older 
charts  various  units  are  found. 

In  the  first  group  feet  are  ordinarily  found  only  on 
large  scale  or  local  charts  of  areas  with  moderate 
depths,  and  the  other  charts  are  in  fathoms,  except 
that  on  the  earlier  charts  of  the  Coast  and  Geodetic 
Survey  feet  were  used  on  a  sanded  surface  inside  of  the 
three-fathom  curve  and  fathoms  on  the  white  surface 
outside  of  that  curve.  Heights  are  stated  in  feet  on 
the  charts  of  the  first  group. 

Plane  of  reference.  As  the  depth  of  water  varies 
with  the  tide,  it  is  necessary  for  charting  purposes  to 
adopt  some  standard  plane  to  which  the  soundings  are 
referred.  Practically  all  countries  have  adopted  for 
this  purpose  a  low  stage  of  the  tide,  as  this  is  obviously 
on  the  side  of  safety;  in  most  cases  an  extreme  low 
water  is  used,  so  that  the  actual  depths  will  seldom, 
owing  to  the  tide,  be  less  than  those  shown  on  the  chart. 
The  definite  reference  planes  used  on  the  American 
charts  will  be  mentioned  later. 

On  nearly  all  charts  heights  are  referred  to  mean  high 
water,  doubtless  owing  to  this  being  the  visible  limit  of 
the  land  at  high  tide.  On  topographic  maps  of  the 
interior,  the  heights  are  referred  to  mean  sea  level, 
which  plane  is  of  course  lower  than  the  preceding  by 
one-half  the  range  of  tide. 

Symbols  on  charts.  Fair  uniformity  as  to  general 
principles,  with  differences  as  to  details  in  carrying 
them  out,  exists  on  the  various  series  of  charts  regard- 
ing their  general  arrangement  and  the  more  important 
symbols,  such  as  in  the  shading  of  land  to  distinguish 


Desirability  of  Uniformity  in  Charts  21 

from  water,  the  use  of  depth  curves,  the  representation 
of  hills  by  shade  or  contour,  the  indication  of  shoals 
and  dangers,  and  of  lighthouses  and  buoys. 

Desirability  of  uniformity  in  charts.  Ships  engaged 
in  international  commerce  must  enter  foreign  ports. 
As  the  information  is  constantly  changing  and  charts 
are  being  corrected  or  improved,  it  is  sometimes 
desirable  for  the  navigator  to  consult  the  local  foreign 
charts,  and  it  may  often  be  necessary  for  him  to  carry 
in  his  chart  room  the  charts  of  several  different  coun- 
tries. There  are  therefore  important  advantages  in 
international  uniformity  in  chart  publication. 

There  should  be  a  common  initial  longitude,  and  as 
the  longitude  of  Greenwich  has  been  so  extensively 
adopted,  it  appears  quite  probable  that  its  use  may 
some  day  become  universal. 

A  common  unit  for  soundings  and  heights  would  be 
very  desirable,  but  the  fact  that  a  large  group  of  nations 
has  united  on  the  metric  system,  while  a  small  group 
with  great  commercial  interests  retains  another  system, 
makes  the  attainment  of  uniformity  difficult. 

Substantial  agreement  as  to  the  use  of  symbols  on 
charts,  particularly  such  as  represent  aids  or  dangers 
to  navigation,  would  be  desirable  and  doubtless  feasible. 

Privately  published  charts.  Many  of  the  earlier  charts 
were  prepared  and  published  by  private  enterprise,  and 
such  charts  are  still  published,  as,  for  instance,  the  so- 
called  " blue-back"  charts  printed  in  London.  These 
charts  have  usually  differed  from  those  published  by 
the  various  governments  either  in  representing  the  main 
features  in  a  very  bold  manner  with  little  detail  or  in 
including  a  considerable  area  with  many  plans  on  a 


Charts  and  Maps 


single  large  sheet  backed  for  permanency.  An  objec- 
tion to  the  latter  is  that  the  durability  together  with  the 
high  price  tends  to  keep  an  old  chart  in  use  long  after 
it  is  out  of  date.  It  would  be  financially  difficult  for 
a  private  firm  to  give  the  service  that  a  government  does 
in  the  matter  of  correcting  the  charts  and  issuing  new 
editions,  and  this  is  an  important  consideration  in  the 
selection  of  charts. 

Purpose  of  charts.  The  main  purpose  of  charts  is  to 
furnish  graphical  guides  to  aid  in  taking  a  vessel  safely 
from  one  port  to  another;  they  are  maps  for  the  use  of 
navigators.  An  experienced  mariner  may  be  able  to 
steer  his  vessel  over  a  familiar  course  without  charts, 
but  this  does  not  make  their  publication  less  necessary. 
Even  such  an  expert  pilot  doubtless  studied  the  charts 
in  the  first  place;  the  uncertainties  of  the  sea  and 
the  changes  of  information  are  such  that  his  vessel's 
equipment  should  include  the  latest  charts,  and  safety 
requires  their  examination.  The  passengers  and  the 
merchants  who  intrust  their  lives  or  their  goods  to  the 
sea  are  largely  dependent  upon  the  correctness  of 
the  charts. 

Besides  their  main  purpose  charts  fill  many  other 
needs,  among  which  are;  for  preliminary  planning  of 
harbor  improvements  and  various  engineering  works, 
for  defensive  works  and  other  military  uses,  for  the 
fishing  interests,  and  for  general  information  as  to  the 
coastal  regions.  Charts  will  furnish  much  of  interest 
and  instruction  to  the  traveler  by  sea  and  the  dweller 
near  the  coast,  who  will  learn  to  read  them.  Passenger 
steamers  should  more  often  for  the  interest  of  their 
patrons  display  charts  of  the  waters  traversed.  No 


Requirements  for  Charts 


written  or  verbal  description  can  give  as  clear  an  idea 
of  geographical  features  and  relations  as  a  good  map 
or  chart. 

As  the  charts  are  revised  from  time  to  time,  a  com- 
parison of  editions  at  different  dates  furnishes  a  record 
of  the  changes  wrought  by  nature  or  man,  and  this  is 
especially  useful  in  studying  the  action  in  many  harbor 
and  river  entrances,  as  well  as  for  historical  purposes. 

Requirements  for  charts.  As  charts  are  maps  of  the 
water  areas,  including  the  adjoining  land,  and  intended 
primarily  for  the  use  of  mariners,  they  differ  in  impor- 
tant respects  from  topographic  maps  or  general  maps, 
even  such  as  include  the  water  areas.  The  main 
requirements  for  charts  are  these;  correct  and  complete 
information,  early  publication  of  new  data,  clear  and 
intelligible  representation  of  the  information,  conven- 
ient arrangement  as  navigational  instruments,  and  high 
standard  of  publication. 

The  special  and  sometimes  difficult  conditions  under 
which  charts  must  be  used  on  shipboard  call  for  good 
judgment  throughout  their  preparation.  Even  the 
paper  on  which  they  are  printed  is  of  importance,  in 
order  that  they  may  be  sufficiently  durable  and  suitable 
for  plotting. 

Information  given  on  charts.  It  is  evident  that  it  is 
impossible  to  represent  on  a  chart  of  any  practicable 
scale  all  the  features  that  exist  on  the  corresponding 
area  of  the  earth's  surface.  It  is  essential,  therefore, 
that  a  selection  be  made  of  the  classes  of  facts  that  are 
to  be  shown,  as  well  as  of  the  detail  that  is  to  be  used  for 
each  class.  The  practical  utility  of  the  chart  depends 
largely  on  the  good  judgment  used  in  this  selection.  In 


24  Charts  and  Maps 


the  information  shown,  charts  differ  from  maps  prin- 
cipally in  representing  by  soundings  and  curves  the 
configuration  of  the  bottom  of  the  water  area,  and  in 
showing  ordinarily  the  topographic  features  only  in  the 
vicinity  of  the  coast  line. 

The  convenience  of  mariners  should  govern  in  the  se- 
lection and  arrangement  of  the  information  to  be  shown 
on  charts,  though  they  may  be  made  useful  for  other 
purposes  so  long  as  this  convenience  is  not  lessened. 
The  needs  and  preferences  of  navigators  alone,  how- 
ever, differ  so  much  that  a  reasonable  chart  must  be 
somewhat  of  a  compromise  between  conflicting  views. 
For  certain  classes  of  navigation  a  boldly  drawn  chart 
showing  only  the  dangers  and  a  few  other  soundings 
and  some  landmarks  might  be  useful.  For  other 
maritime  purposes  a  more  detailed  chart  would  be 
valuable.  The  first,  however,  would  fail  to  give  facts 
often  demanded  in  the  navigational  use  of  the  chart, 
and  the  second  if  carried  to  an  extreme  would  make  a 
chart  difficult  to  use. 

Shoals  and  dangers  are  shown  either  by  the  least 
depth  or  by  rock  or  reef  symbols.  The  characteristic 
soundings  are  shown  on  the  chart,  with  abbreviations 
indicating  the  nature  of  the  bottom.  Depth  curves 
are  drawn,  joining  together  points  of  like  depth,  and 
inclosing  areas  of  less  depth,  on  the  same  principle 
that  contours  are  used  on  land  maps;  usually  also  the 
shoaler  spots  are  made  more  prominent  by  sanding 
or  tinting  the  area  within  them.  Lighthouses,  buoys, 
and  other  artificial  aids  to  navigation  are  represented, 
with  descriptive  abbreviations.  The  coast  is  shown 
by  a  bold  solid  line  for  high  water  and  a  dotted  line 


Cliffs  and  Rocky  Coas 
Line,. 


Low  Water  Line  and 
Sand  Dunes 


Deciduous  Trees 


»:&**&;  *3% 
-StepP  X<A 

fr&'j&n' 

V  •  gjffi'"a- 


Pine  Trees 


Curves  of  equal  eleva- 
tion and  intermediate 
curves 


Salt  Marsh, 


Coral  Ledge  covering 
and  uncovering 


fathom  curve,shoum  thus 


QandlOOfm.  curves, 
shown  thus: 


MW&pA 

**%*$& 


\;* 


fipS 

*>•£*.' **V^*** 


Lighthouse „ _ _ 

Lighthouse  on  small 
scale  chart _..,. 

Old  light  tower 

Beacon,  lighted 

Beacon,  not  lighted 

Spindle  (or  stake) 

Lightship.,      

Wreck  _ -- 

Anchorage      , 

Rock  awash 

Sunken  rock 

Kelp, 

^o  bottom  at  20 

fathoms. ..._ 

Red  buoy _ 

Black  buoy  

Horizontally  striped 
buoy 

Perpendicularly 
striped  buoy 

Buoys  ivith  perch  and 

square 
Buoys  rvith  perch  and 
ball 

Lighted  buoy „.. 

Mooring  buoy 

Landmark,  as  Cupola, 
Standpipe,  etc, 

Tide  rip ...._ __. ._ 

Current,  not  tidal,  in 
knots _„ 

Current,  flood  in  knots 
Current,  ebb. 

House 

Church — - - 

Public  Road 

Railroad 

Path  or  Trail...... 


2 

I 

$515 


FIG.  6.      SYMBOLS   USED   ON  CHARTS   OF  THE    UNITED   STATES   COAST  AND 
GEODETIC    SURVEY. 


C27) 


Information  Given  on  Charts 


for  low  water.  The  main  topographic  features  are 
represented  for  a  moderate  distance  from  the  coast, 
with  such  detail  as  is  useful,  depending  on  the  scale  of 
the  chart.  Elevations  are  given  in  figures  for  promi- 
nent summits,  islands,  and  rocks;  the  general  configu- 
ration of  hills  and  mountains  is  represented  by  contours 
on  large  scale  charts  or  by  hachures  or  shading  on 
small  scale  charts.  Rivers,  streams,  lakes,  marshes, 
towns,  roads,  prominent  buildings,  and  other  important 
topographic  features  are  shown  by  appropriate  symbols. 
It  is  important  that  objects  which  may  be  useful  in 
navigation  as  landmarks,  whether  natural  or  artificial, 
be  plainly  shown  and  described,  if  necessary  to  their 
identification,  and  that  they  should  not  be  obscured 
by  details  of  lesser  importance.  On  the  larger  scale 
charts  only,  vegetation  features,  particularly  areas 
covered  by  trees,  are  represented  by  symbols.  The 
land  area  is  usually  clearly  distinguished  from  the 
water  area  by  a  tint  or  stipple.  Latitude  and  longitude 
are  given  by  the  projection  lines  and  the  subdivided 
border,  or  sometimes  on  harbor  plans  by  a  note  giving 
the  position  of  some  one  point.  Brief  information  as 
to  the  time  and  range  of  the  tides  is  stated  in  a  note. 
Data  regarding  currents,  whether  due  to  tidal  or  other 
causes,  are  given  by  current  arrows  placed  on  the  chart, 
or  by  explanatory  notes.  Compasses  are  for  conven- 
ience printed  on  the  charts,  and  data  given  as  to  the 
magnetic  variation  and  its  rate  of  change.  On  large 
scale  charts  scales  are  provided  for  use  in  measuring 
distances.  Ranges  and  channel  lines  are  given  when 
required.  The  ports  are  indicated  where  storm  warning 
signals  are  displayed.  The  areas  of  forbidden  anchor- 


30  Charts  and  Maps 


ages  are  shown,  and  when  important,  the  positions  of 
submarine  cables.  The  lines  dividing  the  high  seas 
from  inland  waters  are  sometimes  stated  on  United 
States  charts.  Life  saving  stations  are  given,  and  time 
balls  are  usually  noted.  Views  of  important  features 
are  shown  on  some  charts. 

The  layman  who  looks  at  the  printed  chart  probably 
does  not  appreciate  the  amount  or  the  variety  of 
information  that  must  be  gathered  and  sifted  and  put 
in  proper  shape  for  a  single  chart. 


COLLECTION  OF  INFORMATION  FOR  CHARTS 

Need  of  thorough  surveys.  As  has  been  stated,  a 
good  chart  requires  that  a  thorough  and  correct  survey 
be  first  made  of  the  region  to  be  charted.  It  is  said 
that  men  are  very  apt  to  accept  as  true  anything  they 
see  on  a  map.  As  to  the  nautical  chart  the  mariner 
is  likely  to  be  somewhat  more  critical,  however,  and 
it  is  well  that  he  is.  The  difficulty  of  charting  an 
invisible  surface  such  as  the  bottom  of  the  sea  is  great, 
and  the  proportion  of  the  navigable  waters  surveyed 
in  sufficient  detail  to  be  at  all  certain  of  the  absence  of 
uncharted  dangers  is  small. 

The  planning  of  surveys  in  a  new  region,  such,  for 
instance,  as  the  Philippine  Islands,  presents  many 
interesting  problems,  on  the  solution  of  which  the 
effectiveness  in  chart  results  and  the  cost  of  the  work 
materially  depend.  Many  local  conditions  must  be 
taken  into  account.  The  surveys  are  made  on  opposite 
coasts  according  to  the  seasonal  winds  and  rainfall. 
In  some  parts  fair-sized  steamers  are  necessary;  in 
others  launches  and  small  boats  can  do  the  work 
more  economically.  Shore  parties  with  land  trans- 
portation are  used  for  portions  of  the  work  where  the 
country  permits.  Natives  are  employed  as  far  as 
practicable  for  the  classes  of  work  they  can  do;  the 
Filipinos,  for  instance,  make  good  sailors  on  the  vessels 
and  excellent  penmen  in  the  office. 

The  following  is  a  brief  outline  of  the  steps  of  a  com- 

31 


32  Collection  of  Information 

plete  survey  for  charting  purposes,  according  to  the  pres- 
ent practice  of  the  United  States  Coast  and  Geodetic 
Survey.  These  are  given  in  their  logical  order,  though 
in  actual  work  this  order  must  often  be  departed  from. 
In  this  Survey  the  methods  of  control  have  been  of  a 
high  standard;  that  is,  the  main  stations  have  been 
accurately  determined  and  permanently  marked  and 
described,  and  this  has  proven  an  advantage  in  the 
joining  together  of  the  original  surveys  and  resurveys. 

Astronomical  observations.  To  locate  on  the  sur- 
face of  the  earth  the  area  to  be  charted,  astronomical 
observations  are  required  for  the  latitude  and  longitude 
of  one  or  more  points.  In  the  best  practice  the  longi- 
tude of  a  point  is  obtained  by  observing  the  transits 
of  stars  to  get  the  local  time,  and  sending  time  signals 
by  telegraph  to  obtain  the  difference  from  the  local 
time  of  some  other  place  whose  longitude  is  known. 
The  latitude  is  observed  by  measuring  the  difference 
of  zenith  distance  of  pairs  of  stars  crossing  the  meridian 
north  and  south  of  the  zenith.  The  azimuth  or  true 
direction  of  some  line  is  also  obtained  from  star 
observations,  usually  by  observations  with  a  theodolite 
on  a  circumpolar  star.  Much  existing  chart  work 
depends  on  positions  determined  by  less  accurate 
methods,  as,  for  instance,  longitudes  obtained  by  trans- 
porting chronometers  between  the  known  station  and 
that  to  be  determined,  or  by  observations  of  moon  culmi- 
nations, and  latitudes  obtained  by  direct  observations 
of  the  altitudes  of  stars  with  theodolite  or  sextant. 

Triangulation.  The  main  framework  of  the  survey 
consists  of  a  series  of  triangles  connecting  prominently 
located  points  which  are  permanently  marked  in  the 


JwW- 

i  fathom  and  less     I 

5  ,„„,  . 

jgSSSSS^sa^^^ 

xiC£rjt  '•.'." 

10 

v^JS^^^ 

20  



Trees  

^£  ®Ha 

At|3L 

Rock  or  Shoal  whose 
existence  is  known,  but 
the  position  doubtful 

(+}P.D.  (5)P.D. 

Villages  and  toivns  — 

,    UL_ 

Reported  Rock  or 
Shoal  whose  existance 
is  doubtful 

OD- 

0E.D.  £|E.D. 

£     HP 

Gaslight  Buoys  

4 

Rocky  ledges  which 

Bell  Buoys  ~  

Jl 

cover  and  uncover  _ 

Can  Buoys,.  

\V.      V.S.    Cheq. 

a     JK    ~s- 

^~-v_^- 

-m     -M-.    -M 

R.          B.       H.S. 

Sand  and  mud' 
(dry  at  Low  Water) 

Conical  Buoys  

W.      V.S.    Cheq. 

A.  A.A 

ik     fc    A 

^.  j^.   A 

R.         B.      H.S. 

Stone  bank  and  beach 
(dry  at  Low  Water) 

•*:%$      

Nun  Buoys  _... 

Jk, 

Coral  Reefs  .-...  

t                 fc 
>%            \ 

Spherical  Buoys  „.._  

^ 

%.,         ^ 

Buoys  with  Beacons 

4111 

-SS^  -4S   4P-    4* 

Rocks  with  less  than 
6  feet  at  Low  Water 

£5    © 

Spar  Buoys    ,  

^ 

/ 

Rocks  a  ic  ash  at  Loiv 
Water 

&     0 

Lighthouses 
(position  of)  —  .... 

(«_^ 

Rocks  with  limiting 
danger  line 

{•S'T:^ 
<•!>-••••.*/ 

Floating  Light  Vessels. 
(With  as  many  Masts  & 
balls  as  there  are  lights, 
forming  distinguishing 
marks  by  day) 

y^.  ^I4_ 

Shoal  Banks  which  do 

f§k     4% 

Anchorage  for  large 
vessels 

& 

not  uncover,  where  the 
depth  is  known 

^11  ^ 

Anchorage  for  small 

I    JL 

Overfalls  and  Tide  rips 
Eddies  

-'^"^?l^^fe- 

(9  (9v§> 

Currents  are 
represented  by  -  
Flood  tide  stream  
Ebb  tide  stream  

> 

FIG.  7,      SYMBOLS    USED   ON    CHARTS   OF  THE    BRITISH    HYDROGRAPHIC   OFFICE. 

(33) 


FIG.   9.     TRIANGULATION    STATION    AND    SIGNAL,    ON    ALASKA    COAST. 


FIG.    10.     MEASURING    ANGLES    WITH    THEODOLITE    AT    TRIANGULATION 
STATION    ON    ALASKA    COAST. 


(37) 


Topography  39 


ground  and  the  location  described  so  that  they  can  be 
found  at  a  future  time.  At  long  intervals  in  the  survey 
base  lines  are  laid  out  and  carefully  measured  with  steel 
tape.  Signals  are  erected  over  the  points,  including 
those  at  the  ends  of  the  base  line,  and  angles  are  then 
measured  at  the  various  stations.  From  the  measured 
length  of  the  base  and  the  angles  the  lengths  of  the 
sides  of  the  triangles  are  computed,  and  from  these 
lengths  and  the  latitude  and  longitude  of  one  point  the 
latitudes  and  longitudes  of  all  the  other  points  are 
obtained.  When  several  astronomically  determined 
points  are  connected  by  such  a  triangulation  a  com- 
plication arises  from  what  is  known  as  "deflection 
of  the  plumb  line,"  which  is  the  angular  amount  by 
which  the  actual  sea-level  surface  of  the  earth  departs 
from  the  symmetrical  figure  of  revolution,  owing  to  the 
variations  in  the  density  of  the  earth's  outer  layers. 
The  distance  between  two  points  as  measured  by  trian- 
gulation thus  differs  from  the  distance  computed  from 
the  astronomically  determined  positions.  If  this  irregu- 
larity were  not  taken  care  of  by  adopting  mean  positions, 
the  discrepancy  in  joining  up  different  surveys  would 
in  extreme  cases  amount  to  about  half  a  mile. 

Survey  sheets  are  next  prepared,  of  suitable  size  and 
scale.  On  each  sheet  a  projection  is  laid  down,  that  is, 
the  meridians  and  parallels  are  drawn,  and  all  the  points 
determined  in  the  triangulation  are  plotted  in  their  true 
relation.  Usually  separate  sheets  are  prepared  for  the 
topography  or  shore  survey  and  for  the  hydrography 
or  survey  of  the  water  area. 

Topography.  The  topographic  survey  of  the  shore 
and  as  much  of  the  adjacent  area  as  is  required  is 


40  Collection  of  Information 

usually  made  with  a  plane  table,  on  which  the  map  is 
actually  drawn  in  the  field  as  the  work  progresses. 
Points  are  located  on  the  plane  table  sheet  either  by 
direct  reading  of  the  distance  on  a  stadia  rod  or  by 
intersections  from  two  or  more  stations.  On  the  plane 
table  sheet  it  is  customary  to  locate  the  shore  or  high- 
water  line,  the  low- water  line,  off-lying  rocks,  streams, 
rivers,  roads,  towns,  lighthouses,  and  all  prominent 
features  near  the  coast.  Elevations  are  measured  with 
the  plane  table  or  obtained  from  the  triangulation,  and 
are  represented  on  the  sheet  both  by  figures  and  by 
contours,  which  are  lines  joining  together  points  of 
the  same  elevation.  For  instance,  a  100-foot  contour 
represents  the  line  where  a  plane  100  feet  above  sea 
level  would  cut  the  surface  of  the  ground.  It  is  par- 
ticularly important  in  this  topographic  work  to  locate 
accurately  objects  which  are  good  landmarks  and  likely 
to  be  of  use  to  the  mariner.  In  some  regions  auxiliary 
methods  are  used  in  filling  in  the  topography,  as,  for 
instance,  along  a  difficult  coast  each  feature  of  impor- 
tance may  be  located  by  sextant  angles,  or  a  traverse  line 
may  be  run  along  the  shore  by  the  transit  and  stadia 
method. 

The  hydrography,  or  the  survey  of  the  water  area,  is 
of  prime  importance  for  the  chart,  but  in  the  order  of 
prosecution  of  the  work  it  is  convenient  but  not  essential 
that  it  come  after  sufficient  points  have  been  located 
by  the  triangulation  and  topography.  A  hydrographic 
sheet  is  prepared  on  which  all  the  points  are  plotted 
which  will  be  useful.  A  system  of  sounding  lines  is 
then  run  over  the  entire  area  to  be  surveyed,  locating  the 
position  of  the  sounding  boat  at  intervals  by  sextant 


FIG.  II. 


TOPOGRAPHIC    SURVEY    PARTY    AT    WORK    WITH    PLANE   TABLE 

ON    THE    PRIBILOF    ISLANDS. 


FIG.   12.     SURVEY    SIGNAL    OF    IRON    PIPE    ON    THE 
BAR  OFF  THE   MOUTH   OF  THE   YUKON    RIVER. 


(41) 


Is 


FIG.   14.     THE   LUCAS  AUTOMATIC  SOUNDING   MACHINE   FOR   DEPTHS  TO   5000 
FATHOMS,   WITH    ENGINE. 


FIG.  15.     THE   SIGSBEE  SOUNDING    MACHINE  ON  A  SURVEYING  VESSEL. 

(45) 


Hydrography  49 


angles  on  survey  signals  or  by  angles  from  the  shore. 
The  ordinary  method  of  sounding  is  to  cast  a  lead  from 
a  boat  and  read  the  depth  when  the  lead  touches  bottom 
and  the  line  is  vertical,  and  make  note  of  the  nature  of 
the  bottom.  There  is  a  systematic  spacing  between  the 
casts  of  the  lead  and  between  the  lines  passed  over  by 
the  boat,  depending  on  the  depth  of  water  and  character 
of  the  bottom.  For  soundings  in  deeper  water  various 
forms  of  sounding  machines  are  used,  with  weight 
attached  to  a  wire.  For  very  great  depths  a  small  steel 
wire  is  employed  and  the  weight  is  detached  and  left 
on  the  bottom.  The  deepest  sounding  thus  far  made, 
5269  fathoms,  or  nearly  six  miles,  was  obtained  by  this 
method  in  the  Pacific  Ocean  near  Guam. 

The  offshore  soundings  are  made  from  a  surveying 
steamer;  the  inshore  work  is  usually  done  by  a  launch 
or  small  boat. 

So  far  as  the  navigational  use  of  charts  is  concerned  it 
is  important  that  the  hydrography  shall  show  the  limit- 
ing depths  and  the  freedom  from  dangers,  of  channels, 
entrances,  harbors,  and  anchorages.  It  is  also  desirable 
that  the  soundings  shall  be  carried  off  shore  at  least  as 
far  as  the  one-hundred-fathom  curve,  as  with  the  modern 
forms  of  navigational  sounding  machines  it  is  possible 
for  vessels  under  way  to  obtain  soundings  to  this  depth, 
and  such  soundings  may  be  of  value  in  identifying  the 
location  of  the  vessel.  For  depths  greater  than  one 
hundred  fathoms  the  soundings  have  less  direct  value 
to  navigation  except  as  proving  the  absence  of  shoaler 
areas,  but  soundings  throughout  the  oceanic  regions  are 
of  great  geographical  interest  as  well  as  of  direct  prac- 
tical value  in  the  laying  of  cables. 


50  Collection  of  Information 

It  is  obvious  that  the  plan  of  mapping  the  sea  bottom 
by  dropping  a  lead  at  intervals  over  its  hidden  surface 
is  far  from  an  ideal  one.  The  lead  gives  the  depth 
only  at  the  point  at  which  it  touches  the  bottom,  and 
no  information  as  to  the  space  between  the  casts  except 
such  as  may  be  inferred  from  the  relation  of  successive 
soundings.  In  numerous  cases,  after  what  was  con- 
sidered a  very  thorough  survey  of  a  region  had  been 
made,  at  some  later  day  a  pinnacle  rock  or  other  danger 
has  been  discovered.  For  instance,  a  very  detailed 
hydrographic  survey  of  Buzzards  Bay  was  made  in 
1895;  the  sounding  lines  were  run  at  intervals  of  50 
to  100  yards,  and  91,000  soundings  were  made  for  a 
single  sheet.  Within  this  area  the  cruiser  Brooklyn 
in  1902  touched  a  rock  which  was  found  to  have  18 
feet  over  it.  (Fig.  17.)  The  least  depth  in  the  vicinity 
developed  in  the  original  survey  was  31  feet. 

For  the  satisfactory  development  of  hydrographic 
work  some  invention  is  much  needed  which  as  it 
passes  along  the  bottom  will  give  a  continuous  depth 
curve.  Several  devices  have  successfully  accomplished 
this  in  shoal  water,  but  great  credit  awaits  the  in- 
ventor who  designs  something  of  more  general  applica- 
tion. 

Tides  and  currents.  Information  must  be  obtained 
as  to  the  movement  of  the  water,  both  vertical  and 
horizontal.  The  rise  and  fall  of  the  tide  are  obtained 
by  tide  gauges,  either  automatic,  which  draw  a  con- 
tinuous tidal  curve  on  a  roll  of  paper,  or  simple  tide 
staffs,  which  must  be  read  at  intervals.  The  currents, 
whether  due  to  the  tides  or  other  movements,  are 
measured  by  noting  the  movement  of  partially  sub- 


Dragging  for  Dangers  55 

merged  floats.  Less  accurate  but  useful  information 
as  to  currents  is  obtained  from  the  logs  of  vessels. 

Dragging  for  dangers  has  long  been  resorted  to  for 
the  investigation  of  isolated  spots.  A  valuable  and 
successful  means  has  been  employed  recently  of  mak- 
ing sure  that  an  area  is  free  from  shoals  or  rocks 
having  less  than  a  certain  depth.  This  is  done  by 
dragging  through  the  water  a  wire  from  500  to  1400 
feet  long,  and  suspended  at  the  required  depth,  with 
suitable  buoys  and  weights,  and  kept  taut  by  the  angle 
of  pull.  If,  for  instance,  the  wire  is  set  at  a  depth  of 
30  feet  it  will  indicate  the  presence  of  any  obstruction 
of  less  depth  by  catching  on  it  and  upsetting  the  buoys, 
and  such  spots  are  at  once  marked  and  investigated. 
Considerable  work  has  been  done  with  such  drags  in 
the  last  few  years  on  the  Atlantic  and  Gulf  coasts 
and  on  the  Great  Lakes.  This  is  of  course  a  somewhat 
tedious  process  and  gives  no  information  as  to  depths 
greater  than  that  for  which  the  wire  is  set,  but  the 
experience  already  had  indicates  its  great  value.  It 
will  probably  be  found  desirable  in  time  to  thus  drag  all 
water  areas  important  to  navigation  where  the  depth 
is  near  the  draft  of  vessels  and  the  irregular  nature  of 
the  bottom  gives-  indication  of  dangers.  In  extensive 
dragging  operations  near  Key  West  and  in  Jericho  Bay, 
Maine,  a  number  of  shoals  have  been  picked  up  which 
were  not  found  in  the  original  surveys. 

A  remarkable  instance  of  the  value  of  the  drag  was 
the  recent  discovery  of  a  rock  in  Blue  Hill  Bay  on  the 
coast  of  Maine.  This  rock  has  but  7  feet  of  water 
over  it,  and  is  only  6  feet  in  diameter  at  the  top.  It  is 
surrounded  by  depths  of  78  feet,,  from  which  it  rises 


56  Collection  of  Information 

nearly  perpendicularly.  The  original  survey  gave  no 
indication  of  a  danger  here,  and  its  existence  was  not 
suspected  until  it  was  discovered  with  the  wire  drag. 

Another  method  of  dragging  that  has  been  employed 
is  by  means  of  a  pipe  suspended  beneath  a  ship's 
bottom. 

Magnetic  variation.  As  the  compass  is  a  universal 
navigational  instrument,  information  as  to  the  magnetic 
variation  is  needed  for  the  charts.  The  angle  between 
the  direction  of  the  magnetic  needle  and  the  true  north 
is  measured  at  various  points  on  both  land  and  sea, 
and  at  some  stations  these  observations  are  repeated 
after  a  number  of  years.  From  these  results  magnetic 
maps  are  made,  from  which  both  the  variation  and 
its  annual  change  may  be  taken. 

Reports  of  dangers.  Aside  from  the  more  systematic 
surveys  as  outlined  above,  much  information  has 
been  placed  on  the  charts  from  other  sources.  On 
the  earlier  charts  and  on  those  of  more  remote  regions 
at  the  present  day  much  of  the  work  has  been  sketched 
rather  than  surveyed.  Even  in  the  better  surveyed 
portions  reports  come  in  as  to  dangers  or  other  matters 
not  shown,  and  if  of  importance  and  the  report  appears 
to  be  reliable  these  are  sometimes  at  once  put  on  the 
chart  pending  further  investigation,  or  in  other  cases 
an  examination  is  first  made. 

Shoals,  rocks,  and  even  islands  have  in  numerous 
instances  been  shown  on  the  charts  which  no  one  has 
been  able  to  find  again,  and  many  of  them  after 
repeated  searches  have  been  removed.  The  same 
island  or  danger  has  sometimes  been  charted  in  two 
or  more  different  positions  as  reported  at  various 


Reports  of  Dangers  57 

times.  The  treatment  of  such  cases  is  one  of  the 
serious  and  interesting  problems  of  the  chart  maker. 
It  is  generally  less  harmful  to  show  a  danger  which 
does  not  exist  than  to  omit  one  which  does  exist.  On 
the  other  hand  a  non-existing  danger  shown  on  a  chart 
may  be  the  cause  of  actual  expense  and  loss  of  time 
in  compelling  a  vessel  needlessly  to  go  out  of  its 
course. 

It  is  surprising  to  note  with  what  lack  of  care  and  of 
sufficient  evidence  reports  of  dangers  at  sea  have  some- 
times been  made,  and  how  incomplete  are  many  of  the 
reports  even  when  the  existence  of  the  danger  is  beyond 
question.  It  is  unfortunately  true  that  some  of  these 
reports  are  the  result  of  effort  to  escape  blame  for  acci- 
dent by  throwing  the  fault  on  the  chart.  Many  such 
reports  also  result  from  various  illusory  appearances. 
A  large  tree  covered  with  weeds,  an  overturned  iceberg 
strewn  with  earth  and  stones,  a  floating  ice-pan  covered 
with  earth,  the  swollen  carcass  of  a  dead  whale,  a  whale 
with  clinging  barnacles  and  seaweed,  reflections  from 
the  clouds,  marine  animalculse,  vegetable  growth,  scum, 
floating  volcanic  matter,  and  partially  submerged  wrecks 
covered  with  barnacles,  have  been  mistaken  for  islands, 
shoals,  or  reefs.  A  school  of  jumping  fish  has  given  the 
appearance  of  breakers  or  caused  a  sound  like  surf,  and 
tide  rips  have  been  mistaken  for  breakers.  Raper  very 
properly  calls  attention  to  the  obligation  upon  every 
seaman  of  carefully  investigating  doubtful  cases  and 
making  reliable  reports.  "Of  the  dangers  to  which 
navigation  is  exposed  none  is  more  formidable  than  a 
reef  or  a  shoal  in  the  open  sea ;  not  only  from  the  almost 
certain  fate  of  the  ship  and  her  crew  that  have  the 


58  Collection  of  Information 

misfortune  to  strike  upon  it,  but  also  from  the  anxiety 
with  which  the  navigation  of  all  vessels,  within  even  a 
long  distance,  must  be  conducted,  on  account  of  the 
uncertainty  to  which  their  own  reckonings  are  ever  open. 
No  commander  of  a  vessel,  therefore,  who  might  meet 
unexpectedly  with  any  such  danger,  could  be  excused, 
except  by  urgent  circumstances,  from  taking  the  neces- 
sary steps  both  for  ascertaining  its  true  position,  and  for 
giving  a  description  as  complete  as  a  prudent  regard  to 
his  own  safety  allowed." 

As  to  the  older  doubtful  dangers  now  shown  on  the 
oceanic  charts,  it  is  estimated  that  the  positions  may  be 
considered  as  uncertain  by  10  miles  in  latitude  and 
30  miles  in  longitude,  and  areas  of  this  extent  must  be 
searched  to  determine  definitely  the  question  of  their 
existence. 

The  following  are  interesting  or  typical  cases  of 
reported  dangers: 

The  master  of  an  Italian  bark  in  September,  1874, 
reported  sighting  a  large  rock  in  latitude  40°  N.  and 
longitude  62°  18'  W.  Fortunately  for  the  charts  there 
were  two  independent  reports  from  other  vessels  in  the 
same  month  of  sighting  a  partially  submerged  wreck 
in  this  vicinity. 

The  Spanish  steamer  Carmen  was  wrecked  in  1891 
by  running  on  a  rock  off  the  southwest  coast  of  Leyte; 
the  rock  was  reported  to  lie  one  mile  off  shore,  a  dan- 
gerous position  for  vessels  using  Canigao  Channel.  A 
survey  made  in  1903  showed  58  feet  of  water  in  this 
location,  and  that  Carmen  Rock  on  which  the  vessel 
struck  was  really  within  one-fourth  mile  of  the  beach. 
The  rock  had,  however,  for  twelve  years  been  shown  on 


Reports  of  Dangers  59 

the  charts  in  a  position  which  made  it  an  obstruction 
to  navigation. 

The  ship  Minerva  in  1834  was  reported  to  have 
struck  a  rock  near  the  middle  of  the  broad  entrance  to 
Balayan  Bay;  the  fact  that  this  occurred  at  2  A.M. 
indicated  a  very  doubtful  position,  but  it  was  stated 
that  an  American  ship  had  previously  been  wrecked  on 
the  same  rock.  It  consequently  appeared  as  a  danger 
on  the  charts  for  seventy-one  years,  when  a  survey 
showed  no  depth  of  less  than  190  fathoms  in  this  vicin- 
ity, and  it  was  removed  from  the  charts. 

A  British  steamer  was  wrecked  in  San  Bernardino 
Strait  in  1905;  the  master  reported  that  he  was  in  a 
position  where  the  chart  showed  51  fathoms,  and  that 
he  was  H  miles  distant  from  Calantas  Rock,  and  on 
these  grounds  the  finding  of  the  official  inquiry  was  that 
"no  blame  can  be  attached  to  the  master,  officers,  or  any 
of  the  crew  for  the  casualty."  Very  shortly  after  the 
disaster,  the  surveying  steamer  Pathfinder  definitely 
located  the  wreck  and  made  a  survey  of  the  vicinity. 
The  previous  chart  of  Calantas  Reef  was  found  to  be 
fairly  correct,  and  the  stranding  was  determined  to  have 
occurred  well  within  this  reef  in  a  position  where  the 
chart  showed  soundings  of  31  to  4f  fathoms,  and 
i  mile  from  Calantas  Rock,  which  rises  5  feet  above 
high  water. 

A  transport  entering  San  Bernardino  Strait  a  few 
years  ago  ran  on  a  rock  and  was  damaged;  the  position 
was  reported  as  about  two  miles  southeast  of  San 
Bernardino  Island  and  near  the  middle  of  the  passage. 
The  rock  was  not  put  on  the  charts,  as  prompt  investi- 
gation showed  50  fathoms  of  water  in  this  vicinity,  and 


60  Collection  of  Information 

that  in  all  probability  the  transport  actually  touched  a 
small  reef  making  out  from  the  island. 

The  master  of  the  brig  Helen  reported  that  his  vessel 
was  wrecked  on  a  reef  lying  six  miles  from  Rockall. 
When  surveyed  Helen  Reef  was  found  to  be  about 
one-third  this  distance  from  Rockall. 

An  island  has  been  reported  in  eight  different  posi- 
tions, ranging  in  latitude  from  30°  29'  to  30°  42'  N. 
and  in  longitude  from  139°  37'  to  140°  38'  E. 

There  have  been  a  number  of  reports  of  islands 
in  the  area  from  latitude  40°  00'  to  40°  30'  N.  and  longi- 
tude 150°  30'  to  151°  OCX  W.  The  master  of  the  bark 
Washington  reported  in  1867:  "  On  my  passage 
from  the  Sandwich  Islands  to  the  northwest  coast 
of  the  United  States,  when  in  latitude  40°  00'  N.,  in  a 
dense  fog,  I  perceived  the  sea  to  be  discolored.  Sound- 
ings at  first  gave  great  depths,  but  diminished  gradually 
to  9  fathoms,  when  through  the  mist  an  island  was 
seen,  along  which  I  sailed  40  miles.  It  was  covered 
with  birds,  and  the  sea  swarmed  with  seal  and  sea 
elephants."  A  United  States  vessel  searched  in  this 
vicinity  without  seeing  any  indication  of  land,  and 
obtained  soundings  of  2600  fathoms.  A  British  ship 
in  1858  searched  for  fourteen  days  over  this  area  with- 
out finding  anything.  Searches  were  also  made  in  1860 
and  1867  without  success,  and  the  present  charts 
show  no  islands  in  this  part  of  the  Pacific. 

In  a  number  of  cases  erroneous  positions  have  been 
due  simply  to  blunders.  Thus  Lots  Wife,  first  seen 
by  Captain  Meares  in  1788,  was  shown  on  his  chart  in 
latitude  29°  50'  N.,  longitude  156°  00'  E.,  and  stated 
in  his  book  to  be  in  latitude  29°  50'  N.  and  longitude 


Reports  of  Dangers  61 

23'  E.  Massachusetts  Island  by  one  report  was 
in  longitude  177°  05'  E.  and  by  another  in  167°  05'  E. 
The  apparent  blunder  of  10°  is  now  immaterial,  as  the 
island  has  disappeared  from  the  charts  altogether. 
The  Knox  Islands  were  placed  by  the  Wilkes  Exploring 
Expedition  in  latitude  5°  59'  15"  N.,  longitude  172°  02' 
33"  E.  The  old  British  charts  showed  islands  of  this 
name  also  in  latitude  5°  59'  N.,  longitude  172°  03'  W., 
the  longitude  being  doubtless  transposed.  In  the  case 
of  Starbuck  Island,  discovered  south  of  the  equator,  the 
latitude  was  apparently  transposed,  as  on  old  charts 
it  was  also  shown  in  the  position,  latitude  5°  40'  N., 
longitude  156°  55'  W. 

A  pinnacle  rock  can  sometimes  be  located  only  with 
great  difficulty  even  when  known  to  exist.  Rodger 
Rock,  on  which  the  bark  Ellen  struck  and  was 
damaged,  lies  in  latitude  0°  41'  15"  N.  and  longitude 
107°31/E.  It  has  but  three  feet  over  it  at  low  tide.  The 
British  surveying  ship  Rifleman  searched  four  days 
before  finding  it,  although  the  plotted  tracks  showed 
that  she  and  her  boats  had  passed  very  close  to  it. 
This  indicates  that  great  caution  must  be  used  in 
removing  a  reported  danger  from  the  charts. 

The  old  charts  of  the  Atlantic  indicated  a  danger 
30  to  45  miles  to  the  southwest  of  Cape  St.  Vincent. 
This  danger  was  omitted  from  the  charts  about  1786 
owing  to  lack  of  confirmation.  Later,  in  1813  and  1821, 
it  was  reported  that  vessels  were  lost  or  damaged  by 
striking  this  rock.  Soundings  of  over  a  thousand 
fathoms  are  now  shown  on  the  chart  in  this  vicinity 
and  the  rock  no  longer  appears. 

A  comparison  of  a   Pacific   Ocean  chart  of  about 


62  Collection  of  Information 

forty  years  ago  with  one  of  the  present  time  (Fig.  19) 
illustrates  in  a  striking  manner  how  many  doubtful 
dangers,  or  vigias,  have  gotten  on  the  charts  and  how 
after  laborious  search  many  of  them  have  now  been 
removed.  This  condition  was  especially  true  of  the 
Pacific,  owing  to  the  numerous  reports  of  an  indefinite 
nature  from  whaling  ships,  among  whose  captains 
there  was  a  saying  "  that  they  do  not  care  where  their 
ship  is,  so  long  as  there  are  plenty  of  whales  in  sight." 


11 

30 

CHART  OF  1869 

0°                                                  BANKO                    H 

J0° 

MORELL! 

P.O. 

BYER  1.® 
P.D. 

"l^" 

P 

™^»**-*S^ 

i,  REEF  ? 

.^LAYSON  RKS. 
*'      OR  LA8KER 

P              A              C 

I              F              I 

C 

DECIERTA  ?             :S  REEF 

"DECKER? 

VOLCANO 

MASSACHU8ETTI.?/' 

KRUSENSTERN..^: 

CAMIRA 

r°0 

.ID.? 
LAMIRA?<3        ODECIERSTAP 

ID.? 

#  HALCYON  T 
p»             WAKE  l.° 

0               C 

MAURELLE  ?<. 
OR  S.FRANCISCO 

E            &A              N 

WAKE  RK.  piS 

TARQUIN  ? 

«>ID.?. 

ST.BARTOLOMEO  ? 

CASPAR 

^ 

CORNWALLIS  18* 
0                                                                                      17 

••  BARTHOLOMEW  1.  ? 

0°                                                                IS 

0° 

If 

30 

CHART  OF  1903 

0°                                                                    IS 

0° 

3002     x. 
CURE  1.       .0^^  2605 

^     % 
2185  r,  fr.g, 

2870* 
3080 

«  "v^- 

P             A              C 

/              F             I 

C 

3009 

323^          32n 

KRUSENSTERN  RK. 
P.D.  ,3 

y- 

^J7               1625 

orlm 

BREAKERS 

2J25           3100 

"WAKE  i. 

2375                                 2719 

1991            d-y-m-                      d-y-m- 

O             C 

E             A             N 

3049 
d.m. 
2973 

2931 

SCHJETMAN 

RF.Ct) 

1( 

^CASPAR  RICO 
0°                                                                                       170°                                                                                       Ij 

0° 

FIG.  19.     PORTION  OF  CHARTS  OF   1869  AND    1903,   OF  THE   PACIFIC  OCEAN  WEST  OF 
THE  HAWAIIAN   ISLANDS,  TO   ILLUSTRATE  THE   REMOVAL  OF  DOUBTFUL  DANGERS. 


(63) 


FIG.  20.      PORTION  OF   CHART  OF  PONCE    HARBOR,   SCALE    1-20000,  TO  SHOW 
SELECTION  OF  SOUNDINGS   FROM   ORIGINAL  SURVEY  GIVEN   BELOW. 


FIG.  21.      HYDROGRAPHIC    SURVEY  OF  SAME   PORTION  OF  PONCE  HARBOR,  REDUCED 
TO    ONE-HALF  SCALE   OF  ORIGINAL  SHEET. 

(65) 


PREPARATION  OF  INFORMATION  FOR  CHARTS. 

Chart  schemes.  Before  commencing  the  prepara- 
tion of  a  chart  it  is  necessary  to  arrange  a  definite  scheme 
for  it,  and  the  usefulness  of  the  chart  will  depend 
materially  on  this  preliminary  plan,  in  which  must 
be  outlined  its  scale,  size,  limits,  and  features  to  be 
represented.  New  charts  have  sometimes  been  pre- 
pared simply  to  fit  the  surveys  as  they  progressed  or 
to  fill  immediate  or  local  requirements.  It  is,  however, 
desirable  that  general  plans  for  series  or  groups  of 
charts  be  made,  and  with  changing  needs,  information, 
and  conditions  it  is  sometimes  necessary  that  existing 
schemes  be  modified. 

Compilation  of  information.  Considerable  work  must 
usually  be  done  to  get  the  field  records  in  shape  for 
the  published  chart.  The  soundings  must  be  plotted 
and  the  characteristic  depths  selected.  Only  a  part  of 
the  soundings  that  are  made  can  be  shown  on  the 
original  sheet  and  only  a  small  part  of  these  are  used  on 
the  final  chart.  A  selection  is  made  showing  the  least 
soundings  on  shoals  and  bars,  the  channel  depths,  and 
the  characteristic  soundings  in  anchorages  and  other 
areas.  The  original  surveys  are  generally  made  on  a 
considerably  larger  scale  than  that  on  which  the  chart 
is  published,  in  order  that  the  soundings  may  be  more 
thoroughly  plotted.  The  sheets  must  then  be  reduced 
to  the  scale  of  publication,  and  this  can  conveniently  be 
done  by  means  of  photography  or  with  a  pantograph. 


68  Preparation  of  Charts 

The  best  judgment  is  required  in  selecting  the 
important  features  to  be  shown  on  the  chart  and 
omitting  the  less  important  and  not  essential  features 
which  might  tend  to  obscure  the  others.  In  charts  of 
new  regions  where  complete  surveys  are  lacking,  care 
must  be  exercised  in  weighing,  combining,  and  adjust- 
ing information  from  various  sources  and  which  is, 
perhaps,  more  or  less  conflicting. 

Projections.  The  surface  of  the  earth  being  curved, 
there  is  no  possible  system  of  projection  by  which  it  can 
be  represented  on  a  flat  sheet  of  paper  in  an  ideally 
satisfactory  way.  Numerous  methods  of  projecting  the 
earth's  surface  upon  a  plane  have  been  proposed  and 
many  of  them  are  actually  used  for  various  purposes. 
In  general  each  projection  has  qualities  which  are 
valuable  for  certain  uses,  and  deficiencies  which  make 
it  less  valuable  in  other  ways.  Only  four  of  the  different 
projections  need  be  mentioned  here  as  of  special 
interest  in  chart  construction. 

Mercator  projection.  This  is  a  rectangular  projection 
in  which  the  meridians  are  straight  lines  spaced  at  equal 
intervals  and  the  parallels  are  straight  lines  so  spaced 
as  to  satisfy  the  condition  that  a  rhumb  line,  or  line  on 
the  earth  cutting  successive  meridians  at  the  same  angle, 
shall  appear  on  the  developed  projection  as  a  straight 
line  preserving  the  same  angle  with  respect  to  the 
meridians. 

This  projection  may  be  considered  as  the  unrolling 
upon  a  plane  of  the  surface  of  a  cylinder  tangent  to  the 
earth  along  the  equator,  and  upon  which  the  various 
features  of  the  earth's  surface  have  been  projected  in 
such  manner  as  to  satisfy  the  above  requirement. 


Mercator  Projection  69 

On  this  projection  there  is  a  constant  distance  be- 
tween the  meridians,  whereas  on  the  earth  they 
actually  converge  toward  the  poles.  The  distance 
between  the  parallels  increases  in  passing  toward  the 
poles,  approximately  in  the  proportion  of  the  secant 
of  the  latitude.  For  each  small  portion  of  the  map 
the  relative  proportions  are  maintained  as  on  the 
earth. 

Some  characteristics  of  the  mercator  projection  are 
these:  The  meridians  and  parallels  are  all  straight  lines 
and  perpendicular  to  each  other ;  there  is  no  convergence 
of  the  meridians;  the  minute  of  longitude  is  a  constant 
distance  on  the  map;  the  minute  of  latitude  increases  in 
length  from  the  equator  toward  the  poles  but  locally 
retains  its  true  proportion  to  the  minute  of  longitude; 
areas  and  distances  increase  in  scale  with  the  latitude 
so  that  a  given  scale  is  strictly  correct  only  for  one 
latitude;  great  circles  and  consequently  lines  of  sight 
are  curved  lines  excepting  the  meridians  and  the  equator ; 
rhumb  lines  or  lines  having  a  constant  angle  with  the 
meridians  are  straight,  and  for  the  same  angle  are 
parallel  in  all  parts  of  the  chart.  These  qualities  are 
all  rigid  and  the  projection  can  therefore  be  used  for  all 
areas,  small  or  large,  up  to  the  extent  of  the  earth's 
surface,  except  that  it  cannot  be  extended  to  the  poles, 
as  there  the  length  of  the  minute  of  latitude  would 
become  infinite. 

An  interesting  fact  regarding  a  rhumb,  line  oblique 
to  the  meridians  is  that  it  is  a  spiral  continually 
approaching  but  never  reaching  the  pole;  this  spiral 
makes  an  infinite  number  of  revolutions  around  the 
pole,  and  yet  it  has  a  finite  length  for  the  reason  that 


70  Preparation  of  Charts 

the  length  of  each  revolution  diminishes  as  the  number 
of  revolutions  increases. 

The  mercator  projection  has  been  extensively  used 
for  nautical  charts,  for  which  it  presents  important 
mechanical  advantages,  in  that  adjacent  charts  can  be 
joined  on  all  their  edges  while  still  oriented  with  the 
meridian;  all  charts  are  similar;  the  border  may  be 
conveniently  subdivided,  giving  a  longitude  scale  appli- 
cable to  any  part  of  the  chart,  but  a  latitude  scale  that 
may  be  used  in  the  same  latitude  only;  courses  are 
laid  down  as  straight  lines  and  can  be  transferred  with 
parallel  rulers  from  one  part  of  the  chart  to  another 
without  error.  On  a  mercator  chart  an  island  in 
latitude  60°  would  appear  four  times  as  large  as  an 
island  of  the  same  actual  area  at  the  equator,  but 
this  distortion  of  areas,  while  it  gives  erroneous  impres- 
sions on  charts  of  great  extent  in  latitude,  does  not  seri- 
ously affect  the  use  of  the  chart  for  nautical  purposes. 
Areas  may  also  be  correctly  measured  on  a  mercator 
map  by  taking  each  projection  quadrilateral  separately, 
subdividing  it  if  necessary,  and  using  the  published 
tables  of  areas  of  quadrilaterals  in  different  latitudes. 
Although  distance  scales  vary  with  the  latitude,  dis- 
tances can  be  taken  from  this  chart  with  fair  correctness 
by  the  use  of  the  latitude  border  scale  for  the  middle 
latitude,  subdividing  the  total  distance  if  there  is  much 
range  of  latitude.  The  inability  to  take  off  the  great 
circle  or  shortest  course  directly  from  the  mercator 
chart  is  from  a  navigational  point  of  view  a  defect, 
but  the  most  convenient  solution  for  this  appears  to 
be  the  supplementary  use  of  a  gnomonic  chart  as  will 
be  described.  The  fact  that  lines  of  sight  are  not 


"flfiQjjj 

P          A 


A 

EQUATOR 


TE 


FIG.  22.  MERCATOR  PROJECTION  OF  NORTH  PACIFIC  OCEAN,  SHOWING  GREAT 
CIRCLE  ROUTES  YOKOHAMA  TO  PUGET  SOUND,  AND  YOKOHAMA  TO  HONOLULU 
AND  THENCE  TO  SAN  FRANCISCO. 


FIG.  23.      POLYCONIC   PROJECTION   OF  PORTION  OF  NORTH   PACIFIC  OCEAN. 

(71) 


Polyconic  Projection  73 

straight  lines  on  this  projection  is  another  defect,  as 
by  the  plotting  of  bearings  and  angles  on  approaching 
the  land  the  positions  of  vessels  are  located  on  the 
chart;  fortunately,  however,  the  error  due  to  this  cause 
usually  falls  within  the  other  uncertainties  involved  in 
locating  a  ship;  if  need  be  it  would  be  practicable  to 
allow  for  this  curvature.  In  the  polar  regions,  how- 
ever, the  faults  of  the  mercator  projection  become  so 
much  exaggerated  that  it  is  not  used  for  navigational 
purposes,  but  because  of  the  absence  of  commercial 
navigation  there  this  is  a  minor  matter  in  the  general 
question  of  chart  projection.  For  the  plotting  of  origi- 
nal surveys  the  mercator  projection  is  not  suited  and  is 
not  used,  for  the  reasons  above  mentioned. 

Tables  of  "meridional  parts"  are  published  which 
give  the  distance  in  terms  of  minutes  of  longitude  from 
the  equator  to  the  various  parallels;  with  these  tables 
a  mercator  projection  may  readily  be  constructed. 

Airy  proposed  a  graphical  method  of  sweeping  the 
arc  of  a  great  circle  on  to  a  mercator  chart,  and  tables 
are  published  for  this  purpose.  The  method  is  only 
approximate  and  is  limited  in  application,  and  the 
supplementary  use  of  a  gnomonic  chart  would  appear 
to  be  preferable. 

Polyconic  projection.  In  plotting  the  original  surveys 
it  is  essential  that  a  projection  be  used  which  will  for  the 
area  included  on  a  survey  sheet  show  the  points  in  their 
correct  relation  both  as  to  direction  and  distance. 
These  conditions  are  substantially  fulfilled  by  several 
projections,  of  which  the  polyconic  is  used  in  the 
United  States.  If  a  hollow  cone  were  placed  so  that 
it  would  either  be  tangent  to  the  earth's  surface  along 


74  Preparation  of  Charts 

one  of  the  parallels  of  latitude  or  cut  it  along  two 
parallels,  and  the  points  projected  on  to  this  cone,  and 
the  cone  then  unrolled  and  laid  out  flat,  the  result 
would  be  a  conical  projection,  of  which  there  are  several 
variations.  If  successive  tangent  cones  be  used  and 
each  parallel  of  latitude  be  developed  as  the  circum- 
ference of  the  base  of  a  right  cone  tangent  to  the  spheroid 
along  that  parallel,  the  result  is  the  polyconic  projection, 
which  has  been  used  for  field  sheets  and  for  the  large 
scale  charts,  as  well  as  for  the  topographic  maps  of  the 
United  States.  This  projection  has  valuable  qualities 
for  moderate  areas  of  the  earth's  surface,  within  which 
the  scale  is  approximately  uniform,  areas  retain  nearly 
their  true  proportions,  and  great  circles  and  conse- 
quently all  bearings  and  directions  are  approximately 
straight  lines.  The  parallels  of  latitude  are  arcs  of 
circles  with  radiuses  increasing  as  we  recede  from  the 
pole;  therefore  they  are  not  truly  parallel  and  the  length 
of  the  degree  of  latitude  increases  either  side  from  the 
central  meridian.  The  meridians  converge  toward  the 
poles  and  become  slightly  curved  as  we  recede  from 
the  central  one;  the  longitude  scale  is  everywhere  correct, 
but  the  latitude  scale  is  strictly  correct  only  on  the 
central  meridian.  The  angles  of  intersection  of  parallels 
and  meridians  are  right  angles  or  nearly  so.  The 
polyconic  projection  is  not  used  for  very  extensive  areas 
of  the  earth's  surface,  as  for  instance  a  hemisphere. 

Gnomonic  projection.  In  this  projection  the  eye  is 
assumed  to  be  at  the  center  of  the  earth  and  the  features 
are  projected  upon  a  plane  tangent  to  some  point  on 
the  earth's  surface.  It  is  practicable  to  use  this  projec- 
tion for  oceanic  areas,  and  it  has  the  very  important 


LJ  Q 

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UJ    O 

o:  z 
CS  O 


ii 

uj  O 


<i 

X  O 

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he 

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LL   -3   O 
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(0     Long.     SO11    East    <JO     from    1(K)  •  '-! reen,  110-- 


FIG,  25.     NORTH  POLAR  CHART  ON  ARBITRARY  PROJECTION. 


(11} 


Arbitrary  Projection  79 

quality  that  every  straight  line  on  it  represents  a  great 
circle  of  the  earth.  To  obtain  the  great  circle  or 
shortest  course  between  two  points  it  is  therefore  only 
necessary  to  draw  a  straight  line  between  the  points 
on  a  gnomonic  chart.  Because  of  the  great  distortion 
near  the  edges  this  projection  is  not  otherwise  adapted 
to  navigational  use,  and  it  is  employed  only  to  mark 
out  the  general  course,  and  sufficient  points  are  then 
transferred  to  a  mercator  chart.  The  gnomonic  chart 
is  therefore  useful  in  supplementing  the  mercator  chart, 
supplying  its  deficiencies  as  to  convenience  in  marking 
out  great  circle  courses.  The  great  circle  course  can 
be  derived  not  only  more  easily  and  quickly  from  the 
gnomonic  chart  than  by  computation,  but  the  chart  is 
also  to  be  preferred  because  the  course  marked  out  on 
it  will  show  at  once  if  any  obstruction,  as  an  island  or 
danger,  is  met  or  too  high  a  latitude  is  reached.  A 
modified  or  composite  course  can  readily  be  laid  out 
on  a  gnomonic  chart. 

Arbitrary  projection.  The  few  charts  published  of 
the  polar  regions  are  sometimes  on  an  arbitrary  pro- 
jection, in  which  the  meridians  are  straight  lines  radiat- 
ing from  the  pole  and  the  parallels  are  equidistant 
circles  with  the  pole  as  center.  The  latitude  scale  is 
uniform.  At  some  distance  from  the  pole  the  longitude 
scale  becomes  very  much  distorted,  but  the  projection 
is  a  practicable  and  convenient  one  for  the  immediate 
polar  regions.  Gnomonic  and  conical  projections  are 
also  used  for  the  polar  charts,  differing  little  from  the 
foregoing  for  moderate  areas. 

Scales.  Charts  are  published  on  a  variety  of  scales 
to  suit  different  needs  of  navigation,  and  the  usual 


80  Preparation  of  Charts 

classification  depends  on  scale.  In  addition  to  the 
ocean  charts  covering  a  single  ocean  in  either  one  or 
several  sheets  and  intended  for  navigation  on  the  high 
seas,  there  are  for  our  Atlantic  coast  the  following  series  : 

Sailing  charts,  scale  about  f2iriFoo>  ^or  general  coast- 
wise navigation. 

General  coast  charts,  scale  4  0  Q\  0  0 ,  for  local  coastwise 
navigation. 

Coast  charts,  scale  -g0^OQ,  for  approaching  the  coast 
at  any  point  and  for  inside  passages. 

Harbor  and  channel  charts,  of  various  large  scales 
from  -g-^or  t°  6~oooo>  ^or  entering  harbors  and  rivers  and 
passing  through  channels. 

The  expression  of  scales  by  miles  to  the  inch  or  inches 
to  the  mile  is  the  more  familiar.  The  expression  of 
scale  in  the  manner  used  by  the  Coast  Survey  and  by 
most  of  the  European  countries,  by  standard  fractions 
as  80QQO?  meaning  that  any  distance  on  the  chart  is 
soooo  of  the  actual  distance  on  the  earth,  has  some 
advantages.  For  instance,  the  relation  of  these  frac- 
tions gives  at  a  glance  the  relation  of  the  scales  of  the 
charts.  Thus  a  80^00  chart  is  on  a  scale  five  times  as 
large  as  a  4^0-0  cnart 

For  the  more  important  harbors  charts  have  been 
published  on  several  different  scales  to  meet  various 
needs.  Thus  New  York  Harbor  is  shown  on  charts  of 
scales  oi  10000>  4oooo>  soooo>  200000*  400000  anc* 
T2~o  o~o~oT>  eacn  °f  course  including  a  different  area. 

The  selection  of  suitable  publication  scales  is  of 
prime  importance;  a  large  scale  permits  of  greater 
clearness  and  of  showing  more  detail,  but  on  the  other 
hand  restricts  the  area  and  the  points  that  can  be  shown 


FIG.  26.      NEW  YORK  HARBOR,   PORTIONS   OF  CHARTS   ON    FOUR   DIFFERENT  SCALES. 

(81) 


Scales  83 


on  a  single  sheet,  or  else  makes  a  chart  of  excessive 
dimensions.  In  general  in  chart  preparation  the  scale 
should  be  restricted  to  the  minimum  that  can  be  used 
to  fulfill  the  particular  object  and  clearly  represent 
what  is*  desired.  A  chart  of  very  large  scale  is  not 
convenient  for  plotting,  and  a  moving  vessel  may  pass 
quickly  beyond  it  or  into  range  of  objects  beyond  the 
limits  of  the  chart. 


PUBLICATION  OF  CHARTS. 

Methods  of  publication.  An  ideal  process  of  publi- 
cation for  nautical  charts  would  include  the  follow- 
ing features;  rapidity  in  getting  out  new  charts,  facility 
in  reprinting  and  correcting  existing  charts,  clearness 
and  sharpness  of  print,  durability  of  paper  and  print, 
and  correctness  of  scale.  It  is  difficult  to  fulfill  all  these 
requirements  by  any  method  as  yet  developed.  In  the 
Coast  and  Geodetic  Survey  several  different  processes 
are  in  use  at  present;  charts  are  engraved  on  copper 
and  printed  directly  from  the  copper  plate,  or  they  are 
transferred  from  the  copper  plate  to  stone  and  printed 
from  the  stone,  or  a  finished  drawing  is  made  and 
transferred  to  stone  by  photolithography  and  printed 
from  the  stone,  or  an  etching  is  made  on  copper  from  a 
finished  drawing  and  printed  from  a  transfer  to  stone. 
Charts  in  other  countries  are  in  large  part  printed  from 
engraved  plates,  excepting  some  preliminary  charts  by 
lithography. 

Copper  plate  engraving  and  printing  have  long  been 
used  in  chart  preparation.  A  drawing  is  prepared  as 
a  guide  for  the  engraver;  this  must  be  correct  as  to  all 
information  to  be  shown  but  need  not  be  a  finished 
drawing.  A  true  projection  is  ruled  upon  a  copper 
plate.  By  photography  a  matrix  is  made  from  the 
drawing  and  a  wax  impression  taken  from  this  matrix. 
This  is  then  laid  down  on  the  copper  to  fit  the  projection, 
and  the  impression  is  chemically  fixed  on  to  the  copper. 

84 


FIG.  27.      ENGRAVING   A   CHART  ON   A   COPPER   PLATE. 


FIG.  28.     ENGRAVING    SOUNDINGS  ON  A  COPPER  PLATE  WITH  A  MACHINE. 

(85) 


Copper  Plate  89 


The  work  thus  marked  out  is  engraved  by  hand  or  by 
machine.  A  high  degree  of  skill  is  required  in  the 
accuracy  and  finish  necessary  for  chart  engraving. 
Machines  have  been  invented  in  recent  years  which  can 
be  used  for  portions  of  the  work  on  copper  plates,  as 
for  instance  for  cutting  the  sounding  figures,  the 
bottom  characteristics,  the  border  and  projection  lines, 
border  divisions,  compasses,  line  ruling,  and  stipple 
ruling.  Stamps  and  dies  have  been  successfully  used 
for  some  symbols  and  notes,  and  roulettes  for  shading. 
By  means  of  these  various  machines,  many  of  which  are 
American  inventions,  the  process  of  chart  publication 
from  plates  has  been  materially  facilitated. 

When  the  plate  is  completed  an  alto,  or  raised  copy, 
is  made  by  depositing  copper  on  to  it  in  an  electrotype 
vat,  and  from  this  alto  another  basso  or  sunken  copy  is 
made  by  the  same  process.  This  latter  basso  is  used 
in  printing.  A  copper  plate  may  be  used  for  about 
3000  impressions,  after  which  it  may  become  too  much 
worn  for  satisfactory  chart  printing.  By  printing  from 
a  duplicate  basso  the  original  plate  is  preserved  and 
additional  copies  can  be  made  when  needed.  The 
use  of  the  alto  also  greatly  facilitates  matters  when  a 
considerable  correction  to  the  chart  is  required.  All 
the  portions  of  the  chart  to  be  changed  can  be  scraped 
off  the  alto,  and  when  a  new  basso  is  electrotyped  from 
this  scraped  alto  all  such  areas  will  of  course  appear 
as  smooth  copper,  on  which  the  new  work  can  be 
engraved.  Numerous  small  corrections  are  called  for 
on  charts,  and  on  copper  plates  where  these  are  to 
replace  old  work  the  latter  is  removed  either  by  ham- 
mering up  the  back  of  the  plate  or  by  scraping  its  face. 


90  Publication  of  Charts 

Printing  directly  from  plates  is  a  laborious  process. 
After  the  press  bed  has  been  carefully  padded  to  take 
up  inequalities  in  the  plate,  the  surface  of  the  latter 
is  covered  with  ink  and  then  carefully  wiped  off  by 
hand,  leaving  the  ink  only  in  the  engraved  lines.  The 
paper,  first  dampened,  is  laid  on  the  plate,  and  passes 
with  it  beneath  the  cylinder  of  the  press  under  consider- 
able pressure.  The  prints  are  calendered  by  being 
placed  in  a  hydraulic  press  under  600  tons  pressure. 
The  charts  are  beautifully  clear  and  sharp,  not  equalled 
by  other  methods  of  printing.  Owing  to  the  wetting 
and  drying  of  the  paper,  the  finished  print  is,  however, 
quite  appreciably  smaller  in  scale  than  the  plate,  and 
the  shrinkage  is  greater  in  one  direction  than  in  the 
other.  The  average  day's  work  for  one  press  and  two 
men  is  75  prints.  This  is  small  compared  with  the 
output  practicable  with  lithographic  presses.  On  the 
other  hand  a  plate  can  be  prepared  for  printing  more 
readily  than  a  lithographic  stone.  For  small  editions 
the  plate  printing  compares  well  in  economy  with 
lithographic  printing,  and  the  plate  can  also  be  printed 
on  short  notice.  Because  of  changes  in  aids  to  naviga- 
tion and  other  corrections,  it  is  usually  desirable  to 
print  at  one  time  only  a  sufficient  number  of  copies 
of  a  chart  to  meet  current  demands,  and  not  to  carry 
a  large  stock  on  hand. 

The  copper  plates,  bassos,  and  altos  make  a  very 
convenient  and  enduring  means  of  preserving  the 
chart  ready  for  printing  or  for  further  correction.  A 
large  number  of  plates  can  be  placed  in  a  small  space, 
and  if  properly  cared  for  they  may  be  stored  indefinitely 
without  deterioration. 


FIG.  30.     PRINTING  CHARTS   FROM    COPPER   PLATES;    FINAL  CLEANING  OF  THE   PLATE 
BY  HAND;   PLATE   PRESS  ON  THE   LEFT. 


FIG.   31.       LITHOGRAPHING    PRESSES    FOR   PRINTING   CHARTS ;     LITHOGRAPH   STONE 
ON  TRANSFER  PRESS. 

(91) 


Photolithography  93 


With  plate  printing  it  is  not  practicable  to  print 
more  than  one  impression  on  the  chart  or  to  use  more 
than  one  color,  and  plate-printed  charts  are  therefore 
in  black  only. 

Engraving  on  stone.  On  the  United  States  Lake 
Survey  the  charts  are  first  engraved  on  stone,  and  by 
a  special  process  the  work  is  then  transferred  to  small 
copper  plates,  which  are  preserved.  The  final  publi- 
cation is  by  lithography,  transferring  again  from  the 
plates  to  stone. 

Photolithography  is  a  quick  method  of  publishing 
a  chart.  It  would  be  practicable  by  this  means  to 
reproduce  the  original  survey  sheets,  but  ordinarily 
these  are  not  suitable  as  to  scale  and  legibility,  and 
it  is  necessary  to  make  a  new  drawing,  usually  on 
tracing  vellum.  This  is  photographed  on  to  glass 
plates,  on  the  scale  of  the  proposed  chart.  From  these 
glass  negatives  positive  prints  are  made  on  sensitized 
lithographic  paper.  These  prints  are  fitted  together 
and  then  inked,  taking  the  ink  only  where  the  lines 
appear.  This  transfer  print  is  then  laid  face  down 
on  the  lithographic  stone  and  run  through  a  press 
under  pressure,  the  stone  absorbing  the  ink  from  the 
paper.  The  stone  is  then  treated  so  that  the  inked 
portion  remains  slightly  raised,  and  from  this  stone  an 
indefinite  number  of  charts  can  be  printed  in  a  litho- 
graphic press  at  the  rate  of  1000  an  hour.  The  paper 
is  not  moistened,  and  consequently  there  is  little  distor- 
tion or  change  of  scale  in  prints  from  stone.  If  desired 
to  shade  the  land  or  use  another  color  for  any  other 
purpose,  additional  impressions  can  be  made  on  the 
same  charts  from  other  stones.  Because  of  the  bulk 


94  Publication  of  Charts 

of  the  stones,  work  cannot  ordinarily  be  retained  on 
them,  but  the  chart  is  cleaned  off  and  the  stones 
repeatedly  used  until  worn  thin.  The  original  drawing 
as  well  as  the  negatives  is  preserved,  from  which  the 
chart  can  again  be  published.  For  republication,  the 
process  is,  however,  not  entirely  satisfactory;  the 
negatives  are  not  always  permanent,  the  work  must 
again  be  assembled  and  transferred  to  the  stone, 
changes  or  corrections  are  not  very  conveniently  made 
on  either  drawing  or  negative,  and  after  repeated 
changes  the  drawing  becomes  difficult  to  use  in 
photolithography.  Whether  the  charts  are  actually 
printed  from  copper  or  stone,  there  are  decided  advan- 
tages therefore  in  the  matter  of  correction  work  and 
future  editions  in  having  the  charts  engraved  on  copper. 
On  the  other  hand,  the  advantages  of  the  photolitho- 
graphic process  are  the  ability  to  publish  new  drawings 
promptly,  to  use  more  than  one  shade  on  a  chart,  to 
obtain  prints  with  little  change  of  scale  or  distortion, 
and  to  print  large  editions  rapidly. 

Lithographic  printing  by  transfer  from  engraved 
plates.  An  impression  on  transfer  paper  may  be  taken 
from  an  engraved  plate  and  this  laid  down  on  the  stone 
in  a  manner  similar  to  that  used  in  laying  down  the 
prints  from  the  glass  negatives  in  photolithography. 
Prints  are  then  made  from  the  stone  the  same  as 
in  photolithography,  but  with  superior  results  as  to 
clearness.  This  general  process  is  extensively  used 
in  both  map  and  chart  publishing  in  this  country,  as 
it  combines  the  advantages  of  the  plate  in  preservation 
of  the  chart  record  and  facility  of  correction,  and  the 
advantages  of  the  lithographic  printing  in  less  distortion 


Etching  on  Copper  95 

of  the  printed  chart,  ability  to  print  more  than  one  shade, 
and  facility  for  large  editions.  As  the  transfer  from 
the  plate  can  be  readily  made  it  is  also  better  applicable 
to  small  editions  than  is  photolithography.  It  is,  how- 
ever, not  as  convenient  in  the  latter  respect  as  plate 
printing,  and  it  does  not  give  a  resulting  impression 
equal  in  clearness  or  durability  to  the  impression  directly 
from  the  plate. 

Etching  on  copper  for  chart  publication  has  been 
recently  developed  in  the  Coast  and  Geodetic  Survey. 
A  finished  tracing  is  made,  the  surface  of  a  smooth  cop- 
per plate  is  sensitized,  and  by  exposure  to  the  sun  a 
print  is  made  on  the  sensitized  surface.  It  is  essential 
to  use  an  air-exhausted  printing  frame  so  as  to  get 
good  contact  between  the  vellum  and  the  plate.  The 
work  is  then  etched  into  the  copper  and  the  plate 
cleaned  and  touched  up,  after  which  it  may  be  used  the 
same  as  a  hand-engraved  plate,  either  for  transfer  to 
stone  or  direct  plate  printing.  The  expense  and  time 
required  in  the  etching  process  are  much  less  than  for 
hand  engraving.  The  process  has  been  successfully  used 
for  a  number  of  harbor  charts.  The  etching  of  course 
will  be  of  the  same  scale  as  the  vellum  at  the  time  of 
the  print,  and  vellum  varies  somewhat  in  scale  with 
weather  conditions  and  age.  Unless  overcome  by  the 
substitution  of  some  more  invariable  material  in  place 
of  vellum,  this  might  be  an  obstacle  to  the  use  of  the 
process  for  general  charts  where  a  true  scale  on  the 
copper  plate  is  desirable  because  of  future  work  to  be 
done  on  the  plate.  It  must  also  be  taken  into  account 
that  the  etching  requires  a  finished  tracing  in  ink,  which 
is  not  essential  for  the  hand  engraver;  if,  however, 


96  Publication  of  Charts 

the  chart  is  first  published  by  photolithography,  as  is  the 
usual  practice  in  the  Coast  and  Geodetic  Survey,  the 
same  tracing  is  used  for  both  processes. 

Distribution  of  charts.  Charts  published  by  the 
government  are  sold  to  the  public  at  a  small  price, 
estimated  to  cover  the  cost  of  paper  and  printing.  The 
charts  may  be  obtained  direct  from  the  publishing 
office  or  from  the  chart  agents  who  are  to  be  found  in 
all  the  principal  seaports.  Catalogues  are  published 
from  time  to  time  giving  complete  lists  of  the  current 
charts  and  the  main  facts  regarding  them.  Index  maps 
show  graphically  the  area  covered  by  each  chart.  The 
notices  to  mariners  contain  announcement  of  new  charts 
or  new  editions  published  and  of  charts  or  editions 
cancelled,  as  well  as  of  all  corrections. 


CORRECTION  OF  CHARTS. 

Need  for  revision.  The  making  of  the  survey  and  the 
printing  of  the  chart  do  not  complete  the  problem  of  the 
chart  maker.  Both  nature  and  man  are  constantly 
changing  the  facts  the  representation  of  which  has  been 
attempted  on  the  charts,  and  also  the  needs  of  man  are 
always  varying.  The  original  surveys  are  made  to 
meet  the  reasonable  requirements  of  the  time,  but 
breakwaters  and  jetties  are  built,  and  channels  and 
harbors  dredged  and  otherwise  improved,  and  cities 
built,  and  new  paths  of  commerce  are  opened  which 
bring  vessels  into  waters  previously  thought  of  minor 
importance. 

With  the  increase  of  commerce  and  speed  of  vessels 
more  direct  routes  are  demanded  for  reasons  of  econ- 
omy. Inside  routes  not  originally  used  are  sometimes 
developed  for  defensive  reasons.  The  average  draft  of 
the  larger  vessels  has  also  increased  remarkably  since 
the  modern  hydrographic  surveys  were  commenced, 
and  surveys  once  made  to  insure  safety  for  the  deepest 
vessels  of  that  time  are  now  not  adequate.  The  average 
loaded  draft  of  the  20  largest  steamships  of  the  world 
has  increased  as  follows:  1848,  19  feet;  1873,  24  feet; 
1898,  29  feet;  1903,  32  feet.  The  average  length  of 
these  vessels  was  230  feet  in  1848,  390  feet  in  1873, 
541  feet  in  1898,  and  640  feet  in  1903.  The  number  of 
vessels  drawing  as  much  as  26J  feet  rose  from  36  in 
1902  to  185  in  1904.  In  1906  there  were  17  vessels 


98  Correction  of  Charts 

afloat,  drawing  32  feet  and  upwards.  There  are  now 
two  steamers  on  the  Atlantic  790  feet  long,  88  feet  beam, 
and  37^  feet  draft  when  fully  loaded,  and  larger  vessels 
are  already  planned. 

Great  natural  agencies  are  also  constantly  at  work 
effecting  changes  in  features  shown  on  the  charts. 
The  action  of  currents  and  waves  is  continually  cutting 
away  or  building  the  shore,  particularly  on  sandy 
coasts  exposed  to  storms.  When  surveyed  in  1849 
Fishing  Point  on  the  east  coast  of  Maryland  was  but 
a  bend  in  the  shore  line.  By  1887  it  had  built  out 
about  two  miles  in  a  southerly  direction,  and  in  1902 
about  two-thirds  of  a  mile  further,  curving  to  the  west- 
ward. Altogether  in  about  half  a  century  this  tongue 
of  land  has  grown  out  nearly  three  miles. 

Rivers  are  bearing  vast  quantities  of  sediment  and 
depositing  these  near  their  mouths,  pushing  out  the 
coast  line  and  filling  in  the  bottom.  The  main  mouths 
of  the  Mississippi  are  advancing  into  the  Gulf,  but  at 
a  comparatively  slow  rate.  A  break  from  the  main 
river  at  Cubit's  Gap  just  above  the  head  of  the  passes, 
however,  has  done  an  enormous  amount  of  land 
making,  filling  in  an  area  of  about  50  square  miles 
between  1852  and  1905. 

The  mouth  of  the  Columbia  River  in  Oregon  shows 
an  interesting  example  of  the  movement  of  an  island. 
The  chart  of  1851  shows  the  center  of  Sand  Island 
3^  miles  southeast  of  Cape  Disappointment,  the  chart 
of  1870  shows  it  2f  miles  southeast,  and  the  chart 
of  1905  shows  it  1J  miles  easterly.  This  island  has 
thus  moved  2  miles  northwesterly  directly  across  the 
middle  of  the  river  entrance,  closing  up  the  former 


'    .SURVEY  OF 


/'  SOUNDINGS: 
-x                   6  foot  curve     .. 

13    «         «          _ 
is     "        " 


Nautical  Miles 


SURVEY  OF 

• 1902 


l       / 


SOUNDINGS: 
6  foot  curve 


Nautical  Miles 


FIG.  32.      FISHING   POINT,    MARYLAND,    FROM   SURVEYS    OF   I849  AND   I902,   ILLUS- 
TRATING  BUILDING   OUT  OF  A  POINT  ON  THE  COAST. 


(99) 


SURVEY  OF  1852 

SOUNDINGS: 
6  foot  curve 


SURVEY  OF  1905 

\   \  \  SOUNDINGS: 

\     \  \  c  foot  curve ~ — 

\    \  \       a   »       ««      

' 


FIG.  33.     GROWTH  OF   LAND   AT  CUBITS  GAP,  MISSISSIPPI    DELTA,  FROM    1852  TO  1905. 

(101) 


Nautical  Mile 


0  U  1 

FIG.  35,     CHANGES   IN    HAULOVER    BREAK,    NANTUCKET   ISLAND,    1890  TO    1903. 


New  Bogoslof 


DALL  1895 


New  Bogoslof  JAGGAR  1907 


FIG.   36.      MAPS    OF    BOGOSLOF    ISLAND,    1 895   AND    I907,   SHOWING    CHANGES    DUE 

TO  VOLCANIC  ACTION. 

(105) 


Need  for  Revision  109 

north  channel.  The  southern  point  of  the  entrance, 
Clatsop  Spit,  has  built  out  about  the  same  distance. 

Volcanic  action  in  well  authenticated  cases  has 
caused  islands  to  rise  or  disappear.  In  the  present 
location  of  Bogoslof  Island  in  Bering  Sea  the  early 
voyagers  described  a  "sail  rock."  In  this  position  in 
1796  there  arose  a  high  island.  In  1883  another  island 
appeared  near  it.  In  1906  a  high  cone  arose  between 
the  two,  and  a  continuous  island  was  formed  over 
1^  miles  long  and  500  feet  high.  The  latest  report 
(September,  1907)  was  that  this  central  peak  had  sud- 
denly collapsed  and  disappeared.  Bogoslof  is  an  active 
volcano,  and  the  main  changes  have  been  the  result 
of  violent  volcanic  action.  The  history  of  this  island 
for  over  a  century  past  forms  a  remarkable  record  of 
violent  transformations  in  the  sea. 

Earthquakes  sometimes  cause  sudden  displacements, 
horizontal  or  vertical,  of  sufficient  amount  to  affect  the 
information  shown  on  the  charts.  A  careful  investiga- 
tion of  the  effects  of  the  earthquake  in  Yakutat  Bay, 
Alaska,  in  September,  1899,  showed  that  the  shore 
was  raised  in  some  parts  with  a  maximum  uplift 
of  47  feet  and  depressed  in  other  parts,  and  that  at 
least  two  reefs  and  four  islets  were  raised  in  the  water 
area  where  none  appeared  before.  Undoubtedly  there 
were  changes  in  the  water  depths,  but  definite  informa- 
tion is  lacking  because  there  had  been  no  previous 
hydrographic  survey.  The  San  Francisco  earthquake 
of  1906  caused  little  vertical  displacement,  but  there 
were  horizontal  changes  of  relative  position  as  much 
as  16  feet;  so  far  as  known  this  earthquake  did  not 
affect  the  practical  accuracy  of  the  charts.  Related 


110  Correction  of  Charts 

to  earthquake  phenomena  are  the  gradual  coast  move- 
ments of  elevation  or  subsidence  which  are  taking 
place  but  at  so  slow  a  rate  as  not  to  sensibly  affect  the 
charts  in  ordinary  intervals  of  time. 

Another  agency  at  work  is  the  coral  polyp  on  the 
coral  reefs;  although  the  rate  of  growth  appears  to  be 
very  slow,  the  resulting  reefs  and  keys  are  an  important 
feature  in  tropical  seas. 

Practically  all  of  the  land  features  shown  on  charts 
are  likewise  subject  to  changes,  the  more  rapid  of 
which  are  mainly  due  to  the  works  of  man. 

The  changes  of  channels  and  of  commercial  needs 
cause  many  alterations  to  be  made  from  time  to  time 
in  the  lights  and  buoys  which  are  shown  on  the  charts. 

Methods  of  correction.  The  problem  of  keeping  a 
chart  sufficiently  up  to  date  is  one  of  much  practical 
importance  and  one  which  must  be  taken  into  account 
in  planning  what  should  be  shown  on  the  chart  in  the 
first  place  so  as  to  bring  it  within  the  range  of  practi- 
cable revision. 

Certain  features  are  corrected  at  once  on  the  charts 
as  soon  as  the  information  is  received,  such  as  dangers 
reported,  and  changes  in  lights  and  buoys.  Where 
harbor  works  are  in  progress  the  periodic  surveys  made 
in  this  country  by  the  Corps  of  Engineers  furnish  data 
which  are  applied  promptly  to  the  charts.  Reported 
dangers  in  channels  and  bars  are  investigated  by  spe- 
cial surveys  and  the  information  is  put  on  the  charts. 
Examinations  are  made  from  time  to  time  for  the 
revision  of  the  features  along  the  coast  line.  Complete 
resurveys  have  been  made,  at  long  intervals,  of  some 
important  portions  of  the  coast  where  there  has  been 


Methods  of  Correction  111 

evidence  of  change,  and  these,  when  they  become 
available,  are  applied  to  the  charts.  All  parts  of  the 
coast  where  the  exposed  portions  are  not  of  very 
permanent  material  will  require  resurveys  at  intervals, 
depending  on  their  importance  and  the  rate  of  change. 

Notwithstanding  the  great  progress  made  in  hydro- 
graphic  surveys,  a  considerable  number  of  rocks  and 
shoals  dangerous  to  navigation  and  not  previously 
shown  on  the  charts  are  reported,  averaging  nearly  400 
each  year  for  the  last  six  years,  according  to  the  British 
reports.  Of  the  367  reported  in  1906,  11  were  discov- 
ered by  vessels  striking  them. 

Immediate  information  in  the  form  of  Notices  to 
Mariners  is  published,  of  the  more  important  corrections 
to  charts  which  can  be  made  by  hand.  These  correc- 
tions show  what  charts  are  affected,  and  give  sufficient 
data  for  plotting. 

In  the  case  of  extensive  corrections  or  new  surveys 
a  new  edition  of  the  chart  is  printed  and  all  existing 
copies  of  the  previous  edition  are  canceled. 

It  is  important  that  the  user  of  the  chart  shall  make 
certain  that  he  has  the  latest  edition  and  that  all  correc- 
tions from  its  date  of  issue  have  been  applied  from  the 
Notices  to  Mariners. 

It  is  unfortunately  true  that  owing  to  failure  to  take 
proper  account  of  the  notices,  or  to  economy,  old 
editions  or  uncorrected  charts  are  sometimes  used,  and 
in  a  number  of  cases  the  loss  of  vessels  has  been  directly 
due  to  this  cause.  Those  responsible  for  the  safe 
navigation  of  vessels  should  insist  that  the  latest  editions 
of  charts  are  provided  and  that  all  charts  to  be  used  are 
inspected  and  corrected  to  date. 


READING  AND   USING  CHARTS. 

Reading  charts.  A  chart  is  a  representation  on  paper 
of  hydrographic  and  topographic  information  by  means 
of  various  conventional  methods  and  symbols.  It  is 
evidently  important  for  those  making  use  of  charts 
to  understand  the  system  and  conventions  used,  and 
to  be  able  to  interpret  readily  the  various  parts  of 
the  chart.  The  ability  to  read  a  chart  must  include 
an  understanding  of  all  its  features,  such  as  scale, 
projection,  geographic  position,  directions,  depths, 
plane  of  reference,  aids  to  navigation,  tides,  cur- 
rents, elevations,  topography,  and  date  of  survey  and 
publication. 

Scale.  For  American  and  British  charts  the  scale  is 
usually  expressed  by  the  inches  or  fractions  of  an  inch 
to  the  minute  or  degree  of  latitude,  or  by  the  fractional 
proportion  of  a  distance  on  the  map  to  the  correspond- 
ing distance  on  the  earth.  These  fractions  are  some- 
times stated  on  the  British  charts,  and  nearly  always 
on  those  of  the  United  States  Coast  Survey.  The  chart 
catalogues  give  the  scale  in  one  or  the  other  form.  A 
familiarity  with  the  meaning  of  scales  is  of  value  in 
selecting  the  most  suitable  chart,  in  judging  of  the 
relative  uses  of  charts,  and  in  estimating  distances. 
Where  the  fractional  scales  are  stated  they  furnish  a 
simple  means  of  comparing  charts,  as,  for  instance,  a 
chart  on  -s^ov  scale  will  show  all  distances  just  twice 
as  long  as  a  chart  on  TuoWo  scale. 

112 


Scale  113 

The  following  are  scale  equivalents: 

Scale  T^io  o  is  equivalent  to  7.30  inches  to  one  nautical  mile. 

Scale  YO<JO  o  is  equivalent  to  3.65  inches  to  one  nautical  mile. 

Scale  40  ir  oo  is  equivalent  to  1.82  inches  to  one  nautical  mile. 

Scale  -5-0^00  is  equivalent  to  1.46  inches  to  one  nautical  mile. 

Scale  -go  Joo  is  equivalent  to  0.91  inch      to  one  nautical  mile. 

Scale  TooV  o^  is  equivalent  to  0.73  inch     to  one  nautical  mile. 

Scale  so  oVo  o  is  equivalent  to  0.36  inch     to  one  nautical  mile. 

Scale  4ooVoo  is  equivalent  to  0.18  inch     to  one  nautical  mile. 

Scale  TO  otiose  is  equivalent  to  0.07  inch     to  one  nautical  mile. 

Scale  T^OWOO  is  equivalent  to  0.06  inch     to  one  nautical  mile. 


For  use  in  measuring  distances  on  large  scale  charts 
the  length  of  one  or  more  nautical  miles  is  usually 
drawn  on  the  chart,  and  sometimes  scales  are  also  given 
in  other  units.  On  British  charts  the  nautical  mile 
scale  is  divided  into  tenths  (that  is,  cables  of  100  fathoms 
or  600  feet  length)  ;  on  the  American  charts  into  quarters 
and  eighths.  Where  the  scale  covers  more  than  one 
mile  the  fractional  divisions  are  shown  only  for  the  left- 
hand  mile  and  the  zero  of  the  scale  is  placed  between  this 
and  the  full  mile  scale,  so  that  with  dividers  the  full 
miles  and  fraction  may  readily  be  taken  off.  The 
nautical  mile  in  the  United  States  is  taken  to  be  the 
length  of  a  minute  of  arc  of  a  great  circle  on  a  sphere 
whose  surface  equals  that  of  the  earth;  this  definition 
makes  the  nautical  mile  equal  6080.27  feet.  Lecky 
adopts  6080  feet  as  the  nautical  mile.  The  length  of 
the  actual  minute  of  latitude  on  the  earth's  surface 
increases  from  6046  feet  at  the  equator  to  6108  feet  at 
the  poles,  an  increase  of  about  one  per  cent.  It  is, 
however,  this  somewhat  variable  unit  of  length  which 


114  Reading  Charts 

is  ordinarily  used  in  scaling  distances  on  the  sailing 
charts. 

On  small  scale  charts  there  is  usually  a  border  scale 
entirely  around  the  chart,  conveniently  subdivided;  this 
serves  the  double  purpose  of  facilitating  the  plotting  or 
reading  of  positions  by  latitude  and  longitude  and  of 
furnishing  a  scale  of  minutes  of  latitude  for  use  in 
measuring  distances.  On  a  mercator  chart  this  scale  of 
course  varies  with  the  latitude  and  it  must  be  referred 
to  in  the  mean  latitude  of  the  distance  to  be  measured. 
In  general  practice  the  minute  of  latitude  is  taken  as 
equal  to  the  nautical  mile. 

Projection.  On  only  a  few  charts  is  there  a  statement 
of  the  projection  used.  Practically  all  general  sailing 
charts  are  on  the  mercator  projection^  which  can  be 
readily  recognized  by  the  rectangular  network  of  meridi- 
ans and  parallels  and  the  increase  with  latitude  of  the 
distance  between  the  parallels.  On  large  scale  local 
and  harbor  charts  the  kind  of  projection  used  is  not  of 
importance  to  navigation,  as  for  such  limited  areas 
the  difference  between  projections  would  not  affect  the 
use  of  the  chart.  On  certain  small  scale  charts  of  the 
United  States  Court  Survey  which  are  on  the  polyconic 
projection  this  fact  is  stated  on  the  chart,  and  can  also 
be  readily  recognized  by  the  convergence  of  the  meridi- 
ans and  curvature  of  the  parallels.  Gnomonic  charts 
intended  for  taking  off  great  circle  courses  are  always 
described  in  their  titles  and  are  also  easily  recognized 
by  the  increased  scale  and  distortion  toward  all  the 
borders.  Charts  of  the  polar  regions  are  published 
on  several  different  projections,  which  are  distinguished 
from  the  mercator  by  their  circular  or  curved  parallels. 


Geographic  Position  115 

Geographic  position.  For  large  scale  and  harbor 
charts  the  latitude  and  longitude  of  some  point  marked 
on  the  chart  are  sometimes  stated  on  the  face  of  the 
chart.  For  others  of  these,  however,  and  for  smaller 
scale  and  general  charts,  positions  are  obtained  by 
reference  to  the  border  scale.  There  is  a  latitude 
scale  down  either  side  of  the  chart,  and  a  longitude 
scale  across  the  top  and  bottom.  These  scales  are 
conveniently  subdivided  into  degrees,  minutes,  or 
fractions  of  a  minute.  The  minute  is  divided  into 
tenths  (6"),  sixths  (10"),  quarters  (15"),  or  halves 
(30")  on  various  charts. 

Directions  are  indicated  on  charts  both  by  the  projec- 
tion lines  and  by  compass  roses.  Nearly  all  charts  are 
now  oriented  with  the  meridian,  that  is,  north  is  the 
top  of  the  chart,  and  on  a  mercator  chart  the  east  and 
west  border  lines  are  parallel  with  the  meridians  and 
the  north  and  south  border  lines  with  the  parallels. 
Formerly  many  charts  were  not  so  oriented.  Some 
of  these  are  still  in  use  and  can  readily  be  recog- 
nized by  the  diagonal  or  inclined  direction  of  the 
projection  lines  with  respect  to  the  border  of  the  chart. 
Of  course  directions  must  not  be  referred  to  the  border 
lines  of  these  diagonal  charts,  and  scales  along  such 
border  lines  must  not  be  used.  Directions  with  respect 
to  true  north  may  always  be  referred  to  the  projection 
lines  of  the  chart,  but  on  a  polyconic  or  polar  chart 
a  direction  must  not  be  carried  so  far  from  any  projec- 
tion line  as  to  introduce  error  on  account  of  convergence 
of  the  meridians.  Compass  roses  are  placed  on  charts 
to  facilitate  the  taking  off  or  laying  down  of  directions, 
though  in  some  respects  their  use  is  less  accurate  and 


116  Reading  Charts 


convenient  than  the  use  of  protractors,  referring  to 
the  projection  lines.  The  British  charts  and  many  of 
those  of  the  United  States  Coast  Survey  have  only 
magnetic  compasses,  with  degrees  outside  and  points 
inside,  the  former  graduated  to  90°.  These  are  engraved 
on  the  chart  with  the  magnetic  variation  for  the  date 
of  publication,  or  for  a  few  years  in  advance,  and  give 
the  annual  change  in  the  variation.  Because  of  expense 
of  engraving  they  can  be  changed  on  the  charts  only 
at  intervals  of  some  years,  and  until  this  is  done  allow- 
ance for  the  change  in  variation  is  to  be  made  if 
important.  The  German  charts  and  those  of  the 
United  States  Hydrographic  Office  now  have  a  three- 
fold compass,  the  outer  one  degrees  true,  the  middle 
degrees  magnetic  and  the  inner  points  magnetic;  the 
degrees  in  both  cases  are  graduated  to  360°,  reading 
from  north  through  east,  south,  and  west;  thus  north- 
west would  be  stated  as  315°  instead  of  N.  45°  W. 
Small  scale  charts  covering  extensive  areas  have  no 
magnetic  compasses.  They  sometimes  have  true  com- 
passes, and  usually  have  the  isogonic  lines,  or  lines  of 
equal  magnetic  variation,  marked  on  them,  from  which 
the  variation  at  any  intermediate  point  can  be  estimated. 

Depths.  The  unit  used  for  depths  is  always  stated 
plainly  on  the  chart,  and  it  is  important  to  note  this 
carefully,  as  the  British,  American,  and  Japanese  charts 
use  fathoms  for  some  charts  and  feet  for  others,  and 
most  other  countries  use  meters.  Some  of  the  earlier 
charts  of  the  United  States  coast  have  the  depths  inside 
of  the  18-foot  curve  in  feet  and  outside  of  that  curve  in 
fathoms. 

Depth  curves  are  shown  on  charts  in  order  to  bring 


Depths  117 


clearly  to  the  eye  the  different  depth  areas  and  the 
limits  for  navigation  of  vessels  of  various  drafts.  The 
shoaler  areas  are  usually  indicated  by  sanding  the  outer 
limit  or  the  entire  area  within  the  depth  curve.  For 
the  curves  of  greater  depths  various  standard  symbols 
are  used  which  vary  slightly  in  the  different  series 
but  which  may  readily  be  recognized  by  the  soundings 
on  either  side  of  them.  On  the  British  charts  the 
1  and  3  fathom  curves  are  usually  indicated  by  sanding 
the  outer  edge  of  the  areas  of  these  depths  respectively ; 
beyond  these  the  standard  curves  shown  on  these 
charts  are  the  5,  10,  20,  and  100  fathom  curves.  Similar 
curves  are  used  on  the  United  States  charts.  The 
German  charts  show  the  2,  4,  6,  10,  and  20  meter  and 
various  deeper  curves,  and  the  French  the  2,  5,  10,  and 
20  meter  and  deeper  curves.  On  the  United  States 
Lake  Survey  charts  the  areas  included  within  the  6,  12, 
and  18  foot  curves  are  shaded  with  a  blue  tint,  heavy 
along  the  outer  edge,  which  brings  out  strongly  the 
shoal  areas. 

Depth  curves  if  clearly  shown  are  a  great  aid  in  inter- 
preting the  hydrography  and  making  plain  the  shoals 
and  passages.  The  system  of  curves  should  always  be 
understood  when  using  a  chart,  and  it  may  sometimes 
aid  the  navigator  to  trace  out  with  a  pencil  an  additional 
curve,  if  needed,  beyond  the  draft  of  his  vessel.  The 
abbreviations  used  for  the  bottom  characteristics  are 
explained  either  on  the  chart  or  on  the  sheet  of  chart 
symbols,  and  give  information  which  is  useful  in 
anchoring,  and  may  be  helpful  in  identifying  a  position 
by  soundings.  When  a  sounding  is  made  without  the 
lead  reaching  bottom,  the  depth  obtained  is  sometimes 


118  Reading  Charts 

shown  on  the  chart  by  a  short  line  and  zero  above  the 
figure,  indicating  that  at  the  depth  stated,  bottom  was 
not  obtained  (no  bottom).  There  are  a  few  important 
symbols  shown  in  the  water  area  of  charts.  The 
sunken  rock  symbol  indicates  a  dangerous  area,  or  a 
danger  having  a  moderate  depth  of  water  over  it,  or  a 
rock  the  least  water  over  which  is  not  known ;  ordinarily 
on  the  United  States  charts  the  least  depth  will  be  stated 
when  known,  and  the  symbol  omitted.  The  rock 
awash  symbol  indicates  a  rock  awash  at  some  stage  of 
the  tide,  unless  more  definitely  stated.  The  position 
of  a  wreck  is  indicated  by  a  special  symbol.  P.  D. 
(position  doubtful)  and  E.  D.  (existence  doubtful)  are 
placed  after  soundings  or  rocks  or  other  features  which 
depend  on  some  doubtful  report  not  yet  verified. 

The  following  are  the  relations  between  depth  units 
found  on  various  charts: 

1  meter  =  3.281  English  feet  =0.547  English  fathoms. 

1  sajene  (Russian)      =  7         English  feet  =1.167  English  fathoms. 
1  braza(old  Spanish)  =  5.484  English  feet  =0.914  English  fathom. 
1.829  meters  =  6        English  feet  =1.000  English  fathom. 

Aids  to  navigation.  Each  series  of  charts  has  a 
definite  system  of  representing  the  aids  to  navigation; 
these  are  similar  in  principle  but  differ  as  to  detail.  The 
characteristics  of  the  lights,  light-vessels,  buoys,  and 
beacons  are  usually  explained  by  abbreviations  placed 
by  the  side  of  each,  and  the  entire  system  of  representa- 
tion is  given  on  the  explanatory  sheet  for  the  charts. 
Various  methods  of  coloring  lights  and  sectors  and 
buoys  are  in  use  on  different  charts.  It  is  evidently  of 
importance  that  the  user  of  the  chart  should  readily 


Plane  of  Reference  119 

understand  the  significance  of  the  navigational  aids  as 
shown.  For  details  regarding  lights  it  is  of  course 
desirable  to  refer  to  the  light  lists;  for  the  coasts  of  the 
United  States  detailed  buoy  lists  are  also  published. 
Range  and  channel  lines  when  shown  are  represented 
by  distinctive  symbols  with  bearings  indicated.  Danger 
ranges  for  the  avoidance  of  shoals  are  sometimes  shown. 
On  the  British  charts  bearings  as  stated  on  range  and 
channel  lines  are  magnetic;  the  custom  varies  on  other 
charts  and  must  be  carefully  noted  in  each  case. 

Plane  of  reference.  The  soundings  given  on  the 
chart  express  the  depth  of  water  when  the  tide  is  at  the 
height  adopted  for  the  plane  of  reference;  this  same 
plane  is  used  in  the  tide  tables,  which  thus  will  indicate 
the  amount  to  be  added  to  the  soundings  when  the  tide 
is  above  the  plane,  or  to  be  subtracted  when  it  is  below. 
In  order  to  be  on  the  safe  side  the  plane  of  reference 
adopted  is  always  some  low  stage  of  the  tide,  so  that 
there  is  usually  more  water  than  shown  on  the  chart. 

On  the  British  and  German  charts  the  soundings  are 
reduced  to  the  mean  low  water  of  ordinary  spring  tides, 
unless  otherwise  stated.  On  the  charts  of  the  Coast 
and  Geodetic  Survey  the  following  are  the  planes  of 
reference:  for  the  Atlantic  and  Gulf  coasts,  the  mean 
of  the  low  waters ;  for  the  Pacific  coast,  Alaska,  and  the 
Philippines,  the  mean  of  the  lower  low  waters,  except 
for  Puget  Sound  and  Wrangell  Narrows,  where  planes 
two  and  three  feet  lower  respectively  have  been  adopted. 
According  to  the  Tide  Tables  for  1908,  at  New  York 
(Sandy  Hook)  the  tide  will  fall  below  the  plane  of 
reference  on  135  days  during  the  year,  but  the  extreme 
low  tide  will  be  only  one  foot  below  the  plane.  At 


120  Reading  Charts 


Portland,  Maine,  in  1908,  the  extreme  low  water  is  2.1 
feet  below  the  plane,  and  at  San  Francisco  1.5  feet.  Of 
course  when  the  tide  is  below  the  plane  of  reference  the 
amount  must  be  subtracted  from  the  depths  shown  on 
the  chart. 

Strong  winds  and  unusual  barometric  pressure  may 
have  a  marked  effect  on  the  height  of  tide,  so  that  it  may 
differ  appreciably  from  the  predicted  height,  which  is  of 
course  based  on  normal  conditions.  At  Baltimore  and 
at  Willets  Point  observation  shows  that  a  heavy  wind 
may  reduce  the  tide  four  feet  below  the  predicted  heights. 

Tides.  Information  regarding  tides  is  given  on  all 
large  scale  charts,  and  additional  information  and  pre- 
dictions may  be  found  in  the  Tide  Tables.  On  the 
charts  of  the  United  States  coast  there  is  a  small  tide 
table  giving  for  the  high  and  low  waters  the  time  rela- 
tions to  the  moon's  transit  and  the  height  relations  to 
the  plane  of  reference.  On  the  British  charts  there  is 
a  brief  statement  as  to  the  tides  either  at  the  port  on 
the  chart  or  in  the  general  notes ;  this  ordinarily  gives 
the  interval  in  hours  and  minutes  between  the  moon's 
meridian  passage  and  the  time  of  high  water  for  the 
periods  of  full  and  new  moon,  and  also  the  amount  in 
feet  that  the  spring  and  neap  tides  rise  above  the  plane 
of  reference,  and  the  range  of  the  neap  tide.  TJie 
following  is  an  example  of  such  a  tide  note:  "  H.  W.  F. 
and  C.  Campbellton  IVh  Om.  Springs  rise  10  feet, 
Neaps  7  feet." 

At  some  important  ports  information  as  to  the  state 
of  the  tide  is  given  to  vessels,  either  by  means  of  signal 
balls,  or  by  automatic  tidal  indicators,  as  at  the  Narrows 
in  New  York  Harbor,  where  a  large  dial  shows  to 


Currents 


passing  vessels  the  height  of  the  tide,  and  an  arrow 
indicates  whether  it  is  rising  or  falling. 

The  tidal  information  becomes  important  and  must 
be  considered  in  navigation  or  in  anchoring  in  waters 
where  the  available  depth  at  low  water  approximates 
the  draft  of  the  vessel.  In  the  general  use  of  coast 
charts  it  is  also  important  to  observe  the  effect  of  the 
stage  of  tide  on  the  appearance  of  many  features. 
Rocks  rising  some  feet  above  low  water  may  be  entirely 
submerged  at  high  water.  In  some  areas  the  aspect 
may  be  radically  changed  between  high  and  low  water 
by  the  baring  of  extensive  shoals  or  reefs. 

Currents.  Information,  when  available,  as  to  cur- 
rents is  given  either  by  a  note  or  by  current  arrows 
placed  on  the  chart  at  the  position  of  observation. 
Additional  information  as  to  certain  regions  is  given 
in  the  United  States  Tide  Tables.  Tidal  currents, 
flood  and  ebb,  and  currents  not  due  to  tidal  action  are 
distinguished  by  symbols,  and  the  velocity  is  given 
in  knots,  and  on  some  charts  is  indicated  by  the  lengths 
of  the  arrows. 

Complete  and  systematic  current  observations  have 
been  made  in  comparatively  few  localities  because  of 
the  time  and  expense  necessary  to  get  the  full  informa- 
tion as  to  the  variations  of  the  currents  with  the  tides 
and  seasons.  Ordinarily  therefore  the  current  arrows 
shown  on  charts  indicate  only  the  average  direction 
and  velocity,  or  possibly  only  the  conditions  existing 
at  the  season  when  the  survey  was  made.  Oceanic 
and  coast  currents  are  probably  much  less  uniform 
than  might  be  inferred  from  the  current  streams 
drawn  on  maps  and  charts.  A  more  systematic 


122  Reading  Charts 


investigation  of  ocean  currents  is  required  to  fulfill 
the  needs  of  navigation. 

The  tidal  currents  seldom  turn  with  the  tides,  and 
there  may  be  an  interval  of  as  much  as  three  hours 
between  the  time  of  high  tide  or  low  tide  and  slack 
water.  This  leads  to  the  apparent  anomaly  that  in 
cases  the  current  may  be  running  with  its  greatest 
velocity  at  the  time  of  high  or  low  water,  and  may  be 
running  into  a  channel  for  several  hours  after  the  tide 
commences  to  fall.  It  is  therefore,  evidently,  not  safe 
to  draw  inferences  as  to  currents  solely  from  the  tidal 
heights. 

There  are  passages  where  the  tidal  currents  become  of 
the  greatest  importance  to  navigation,  as,  for  instance, 
in  Seymour  Narrows  on  the  inside  route  to  Alaska, 
where  the  current  velocity  reaches  12  knots  and  the 
interval  of  apparent  slack  water  lasts  but  a  few 
minutes. 

Elevations.  The  unit  used  for  elevations  is  also 
stated  on  the  face  of  the  chart,  as  also  the  plane  to 
which  elevations  are  referred.  On  the  United  States 
charts  this  is  generally  mean  high  water  and  on  British 
charts  the  high  water  of  ordinary  spring  tides.  Rocks 
and  islets  usually  have  figures  shown  beside  them, 
either  in  brackets  or  underscored,  which  indicate  the 
height  above  high  water.  Rocks  which  are  bare  at 
low  water  sometimes  have  a  note  " dries"  or  "bares" 
so  many  feet,  indicating  their  height  above  low  tide, 
although  they  are  covered  at  high  tide.  The  British 
charts  in  some  regions  where  there  is  a  large  range  of 
tide  have  underlined  figures  in  the  area  between  high 
water  and  low  water  indicating  the  heights  above  low 


Topography  123 


water,  or  the  depths  of  water  over  the  bank  at  high 
water,  as  explained  in  each  case. 

Topography.  The  land  area  on  most  charts  is 
distinguished  from  the  water  area  by  a  stipple  or  tint; 
on  some  charts  the  topographic  features  have,  however, 
been  depended  upon  to  bring  out  the  land  from  the 
water.  The  solid  shore  line  is  the  high-water  line, 
and  should  be  clear  on  the  chart;  the  area  between 
high  and  low  water  is  sanded  or  otherwise  shaded  on 
all  charts.  The  relief  of  the  land  is  represented  by 
hill  shading  or  by  contour  lines  which  are  the  succes- 
sive curves  of  elevation  on  the  land.  Topographic 
symbols  are  used  for  some  of  the  more  important 
features,  such  as  cliffs,  rocky  ledges,  buildings,  bridges, 
trees,  roads,  etc.  It  is  important  for  the  navigator 
to  understand  the  significance  of  the  hill  representation 
and  the  symbols,  as  they  will  aid  him  in  recognizing  a 
coast  or  island,  and  in  identifying  landmarks. 

Date  of  survey  and  publication.  There  is  usually  an 
authority  note  on  each  chart  showing  the  source  of 
information  or  date  of  survey;  if  on  a  coast  subject  to 
change,  the  latter  is  important.  On  the  United  States 
Coast  Survey  charts  the  date  of  publication  of  the 
edition  is  given,  and  on  British  and  other  charts  the 
date  of  both  large  and  small  corrections.  The  chart 
catalogues  give  the  dates  of  the  last  editions,  or  the 
dates  of  extensive  corrections,  and  this  affords  a  means 
of  seeing  whether  the  copy  of  the  chart  in  use  is  the 
latest  edition  available. 


USE   OF  CHARTS  IN  NAVIGATION. 

Chart  working.  In  crossing  the  open  and  deep  por- 
tions of  the  ocean,  where  the  only  data  given  may  be 
the  projection  lines  and  soundings  far  deeper  than  can 
be  reached  with  navigational  sounding  machines,  the 
chart  is  used  to  lay  out  in  advance  the  general  course 
to  be  followed  and  to  plot  the  positions  of  the  vessel  at 
intervals  either  as  determined  by  observations  or,  lack- 
ing these,  by  dead  reckoning.  When  necessary  the 
courses  of  the  vessel  are  modified  as  the  plotted  positions 
are  found  to  fall  one  side  or  the  other  of  the  proposed 
general  track. 

The  principal  operations  on  a  chart  are  plotting  or 
taking  off  positions  by  latitude  and  longitude,  laying 
down  or  taking  off  bearings,  directions,  and  courses, 
plotting  or  measuring  distances,  and  laying  down  or 
taking  off  angles. 

To  plot  a  position  by  its  latitude  and  longitude  on 
a  mercator  chart,  set  a  parallel  ruler  on  the  adjacent 
parallel  and  then  move  it  to  the  required  latitude  as 
shown  by  the  border  scale  at  either  side;  then  with  a 
pair  of  dividers  at  the  upper  or  lower  longitude  border 
scale  take  the  distance  from  the  nearest  meridian  and 
lay  this  distance  off  along  the  edge  of  the  parallel  ruler. 
The  latitude  and  longitude  of  a  point  are  taken  from  the 
chart  by  reversing  this  process,  or  with  the  dividers 
only.  A  direction  is  laid  down  on  the  chart  or  read 
from  the  chart  preferably  by  using  some  form  of  pro- 

124 


Chart  Working  125 


tractor  and  measuring  the  angle  from  the  projection 
lines.  In  this  country  it  is  more  commonly  done  by 
carrying  the  direction  with  a  parallel  ruler  either  from 
or  to  a  compass  rose  printed  on  the  chart.  Distances 
are  measured  or  laid  down  on  a  mercator  chart  by  using 
the  latitude  border  scale  for  the  middle  latitude.  On 
polyconic  and  other  larger  scale  charts  distances  are 
measured  from  the  scales  printed  on  the  chart.  It 
should  be  remarked  that  in  general  where  special 
accuracy  is  required  distances  should  be  computed  and 
not  scaled  from  any  chart,  because  of  the  error  due  to 
the  distortion  of  paper  in  printing. 

The  use  of  protractors  on  charts  in  plotting  by 
angles  in  the  three- point  problem  will  be  referred  to 
later. 

The  course  to  be  steered  to  allow  for  a  set  due  to 
current  or  wind  may  be  obtained  by  a  graphical  solution 
on  the  chart,  though  it  will  be  preferable  to  do  this  on 
other  paper,  using  a  larger  scale.  (Fig.  38.)  The  direction 
and  velocity  of  the  set  and  the  course  and  speed  of  the 
ship  may  be  considered  as  two  sides  of  a  parallelogram  of 
forces,  of  which  the  diagonal  is  the  distance  and  course 
made  good.  To  obtain  the  course  to  steer  to  reach  a 
given  point  with  a  given  current  and  speed  of  vessel, 
lay  down  the  direction  of  the  destination;  from  the 
starting  point  lay  off  the  direction  of  set  and  the  amount 
in  one  hour;  from  the  extremity  of  this  describe  an  arc 
with  radius  equal  to  the  speed  of  the  vessel  in  one  hour. 
A  line  drawn  from  the  extremity  of  the  direction  of 
set  to  the  point  of  intersection  of  the  arc  and  the  course 
to  be  made  good  will  give  the  direction  of  the  course  to 
be  steered,  and  the  point  of  intersection  will  also  be  the 


126  Use  of  Charts  in  Navigation 

estimated  position  of  the  vessel  at  the  end  of  the  hour's 
run. 

Methods  of  locating  a  vessel.  The  principal  methods 
used  for  locating  the  position  of  a  vessel  are  by  astro- 
nomical observations,  by  dead  reckoning,  by  compass 
bearings,  by  ranges,  by  horizontal  angles,  by  soundings, 
by  vertical  angles,  and  by  sound.  The  full  discussion 
of  these  methods  pertains  to  navigation  and  pilotage, 
and  they  will  be  only  briefly  referred  to  here  as  to  their 
graphical  application  to  charts. 

Astronomical  methods.  There  are  a  number  of 
methods  of  obtaining  the  position  of  a  vessel  by  astro- 
nomical observations.  When  the  position  is  computed 
the  chart  enters  into  these  only  in  the  plotting  of  the 
final  result,  so  that  with  one  exception  these  methods 
will  not  be  referred  to  further  here. 

The  elegant  method  discovered  by  an  American  sea- 
man, Captain  Sumner,  in  1843,  is  in  part  graphical,  to 
be  worked  out  upon  the  chart.  This  method  is  based 
on  the  obvious  fact  that  at  any  instant  there  is  a  point 
on  the  earth  having  the  sun  in  its  zenith  and  which  is 
the  center  of  circles  on  the  earth's  surface  along  the 
circumference  of  any  one  of  which  the  sun's  altitude  is 
the  same  at  all  points.  A  short  portion  of  such  a  circle 
may  be  considered  as  a  straight  line  and  can  be  deter- 
mined by  locating  one  point  and  its  direction,  or  two 
points  in  it.  This  is  known  as  a  Sumner  line.  (Fig.  39.) 

From  an  observation  of  the  sun's  altitude  and  azi- 
muth and  an  assumed  latitude  a  position  is  computed 
and  plotted  and  a  line  drawn  on  the  chart  through  this 
position  at  right  angles  to  the  azimuth  of  the  sun  as 
taken  from  the  azimuth  tables  and  laid  off  from  a 


Dead  Reckoning  129 

meridian.  Another  method  is  to  compute  positions  with 
two  assumed  latitudes  and  plot  the  two  resulting  posi- 
tions and  draw  a  line  through  them.  The  vessel  must 
be  somewhere  on  the  resulting  Sumner  line.  A  good 
determination  may  be  obtained  by  the  intersection  of 
two  Sumner  lines  obtained  from  two  observations  of 
the  sun  with  sufficient  interval  so  that  there  will  be  a 
change  of  azimuth  of  as  much  as  30  degrees  to  give  a  fair 
intersection.  Allowance  must  be  made  for  the  move- 
ment of  the  vessel  between  the  two  observations  by 
drawing  a  line  parallel  to  the  first  and  at  a  distance 
equal  to  the  distance  made  good.  An  excellent  inter- 
section may  be  obtained  by  observation  of  the  sun,  and 
before  or  after  it  of  a  star  in  the  twilight  at  a  different 
azimuth. 

Even  a  single  Sumner  line,  however,  furnishes  valu- 
able information,  as  it  may  be  combined  with  other 
sources  of  information  to  obtain  an  approximation  to 
the  position.  The  vessel  must  be  somewhere  on  this 
line,  and  this  gives  a  good  check  on  the  position  by  dead 
reckoning,  or  an  intersection  may  be  obtained  with  a 
line  or  bearing  of  a  distant  land  object,  or  a  line  of 
soundings  may  be  compared  on  the  chart  with  the 
Sumner  line. 

If  an  observation  is  taken  when  the  observed  heavenly 
body  is  bearing  abeam,  it  is  evident  that  the  resulting 
Sumner  line  will  be  the  direction  of  the  course  of  the 
vessel,  and  this  fact  may  be  useful  in  shaping  the  course 
when  nearing  the  land  or  a  danger. 

Dead  reckoning.  When  impossible  to  obtain  the 
position  by  any  other  means,  it  is  computed  or  plotted 
from  the  last  determined  position,  using  the  courses 


130  Use  of  Charts  in  Navigation 

and  distances  run  as  shown  by  compass  and  log  and 
allowing  for  effect  of  current  and  wind.  Because  of 
uncertainties  in  all  these  elements,  positions  so  obtained 
may  be  from  five  to  twenty  miles  in  error  in  a  two- 
hundred-mile  run,  depending  of  course  to  some  extent 
on  the  speed  of  the  vessel. 

Compass  bearings.  A  compass  bearing  of  a  single 
object,  as  a  lighthouse  or  a  tangent  to  a  point  of  land, 
laid  down  on  the  chart,  shows  that  the  vessel  is  some- 
where on  that  line,  and  when  combined  with  other 
information,  as  with  a  Sumner  line  or  the  course  by  dead 
reckoning  or  the  distance  by  a  vertical  angle,  will  give 
a  position  whose  correctness  of  course  depends  on  the 
accuracy  of  the  data  used.  Bearings  of  two  objects  not 
in  the  same  direction  give  two  lines  on  the  chart  whose 
intersection  is  the  position.  This  will  be  very  weak 
if  the  angle  of  intersection  is  acute,  and  will  become 
stronger  as  it  approaches  a  right  angle.  A  bearing  of 
a  third  object  should  be  taken  when  practicable,  as  it 
affords  a  valuable  check  in  that  the  three  lines  should 
intersect  in  the  same  point;  if  they  do  not  do  so  when 
plotted  the  error  is  either  in  the  observations,  or  the 
compass,  or  the  plotting,  or  the  chart.  (Kg.  40).  All 
compass  bearings  are  of  course  dependent  upon  the 
accuracy  of  the  compass  and  the  knowledge  of  its  errors 
due  to  the  local  magnetic  effect  of  the  ship,  and  also 
upon  the  correctness  with  which  the  magnetic  variation 
from  true  north  is  known.  Bearings  of  near  objects 
should  therefore  always  be  preferred,  and  those  of  dist- 
ant objects  considered  as  giving  only  approximate  posi- 
tions. An  error  of  one  degree  in  the  bearing  of  an  object 
30  miles  away  will  deflect  the  plotted  line  about  one-half 


Compass  Bearings  131 

mile.  Because  of  the  facility  with  which  they  may  be 
taken  compass  bearings  are  much  used  for  inshore 
navigation,  but  in  point  of  reliability  they  are  inferior 
to  some  of  the  other  methods. 

A  single  or  "danger"  bearing  of  an  object  is  often 
a  valuable  guide  in  avoiding  a  danger.  For  example, 
a  reef  may  lie  to  the  westward  of  a  line  drawn  South 
10°  East  from  a  lighthouse;  in  approaching  a  vessel 
will  pass  safely  to  the  eastward  of  the  reef  if  the  light- 
house is  not  allowed  to  bear  any  to  the  northward  of 
North  10°  West.  (Fig.  41.) 

Two  successive  bearings  of  a  single  object,  as,  for 
instance,  a  lighthouse,  noting  the  distance  run  in  the 
interval,  afford  a  convenient  and  much  used  means 
of  locating  the  position  with  respect  to  that  object. 
Such  bearings  are  drawn  on  the  chart  in  reversed 
direction  from  the  object.  The  distance  run  between 
the  bearings,  as  read  by  the  log  and  corrected  for 
current  if  practicable,  is  scaled  off  with  dividers  and 
the  course  of  the  vessel  is  set  off  with  parallel  ruler; 
the  latter  is  then  moved  across  the  two  plotted  directions 
until  the  distance  intercepted  between  them  equals  that 
scaled  with  the  dividers,  and  the  edge  of  the  ruler  then 
represents  the  track  of  the  vessel.  (Fig.  42.)  If  the  angle 
from  the  bow,  or  from  the  course  of  the  vessel,  for  the 
second  bearing  is  double  that  for  the  first  bearing,  the 
distance  from  the  object  at  the  second  bearing  is  equal 
to  that  run  by  the  vessel  in  the  interval,  and  the  use  of 
this  simple  relation  is  designated  as  "doubling  the  angle 
on  the  bow."  If  the  angles  between  the  course  and 
the  object  are  respectively  45°  and  90°  when  the  two 
bearings  are  taken  on  an  object  on  the  shore,  the  dis- 


132  Use  of  Charts  in  Navigation 

tance  that  the  ship  passes  offshore  when  the  object 
is  abeam  is  equal  to  the  distance  run  between  the  two 
bearings;  this  is  a  much  used  navigational  device, 
known  as  the  "  bow  and  beam  bearing  "  or  the  "  four- 
point  bearing."  There  is  an  advantage,  however, 
in  using  bearings  at  two  and  four  points  (or  22°. 5 
and  45°),  as  these  give  the  probable  distance  that  the 
object  will  be  passed  before  it  is  abeam. 

Ranges.  A  valuable  line  of  position  is  obtained  by 
noting  when  two  well-situated  objects  are  in  range, 
that  is,  one  back  of  the  other  in  the  line  of  sight  from 
the  vessel,  as,  for  instance,  a  church  spire  appearing 
behind  a  lighthouse  or  a  rock  in  line  with  a  prominent 
point.  Such  ranges  are  of  course  entirely  free  from 
compass  errors,  and  should  be  noted  whenever  there  is 
favorable  opportunity.  The  value  of  the  range  in  plot- 
ting will  increase  with  the  distance  between  the  objects, 
and  if  the  two  are  close  in  proportion  to  the  distance 
to  the  vessel  the  direction  will  be  weak  owing  to  the 
uncertainty  in  drawing  a  direction  through  close  points. 
Artificial  ranges  are  often  erected  as  aids  to  navigation, 
usually  to  indicate  the  course  to  be  followed  in  passing 
through  a  channel.  Ranges  afford  a  valuable  guide  in 
avoiding  dangers,  as  for  example  an  inspection  of  the 
chart  may  show  that  if  a  certain  lighthouse  is  kept  in  line 
with  or  open  from  an  islet  a  dangerous  shoal  will  be  given 
a  good  berth;  on  coasts  not  well  buoyed  such  danger 
ranges  are  sometimes  marked  on  the  charts.  (Fig.  43.) 

Horizontal  sextant  angles.  The  location  of  a  posi- 
tion by  the  three-point  problem,  using  sextant  angles, 
is  much  more  exact  than  by  bearings,  but  is  less  used 
because  not  so  well  known  and  also  because  additional 


Horizontal  Sextant  Angles  135 

instruments  are  required  and  the  conditions  are  not 
always  favorable.  It  is  so  valuable  a  method,  however, 
that  it  should  be  used,  when  necessary,  on  every  well- 
equipped  vessel.  A  single  horizontal  angle  taken 
with  a  sextant  between  objects,  as  two  lighthouses, 
defines  the  position  of  the  vessel  as  somewhere  on  the 
circumference  of  a  circle  passing  through  the  two 
objects  and  the  vessel.  A  protractor  laid  on  the 
chart  with  two  of  its  arms  set  at  the  observed  angle 
and  passing  through  the  two  objects,  will  permit  of 
locating  two  or  more  points  of  this  circle  on  the  chart. 
This  furnishes  a  line  of  position  which  may  be  com- 
bined with  other  information  to  locate  the  vessel. 
With  a  compass  bearing  of  one  of  the  objects  the 
position  may  be  plotted  directly  from  the  single  angle. 
Two  sextant  angles  measured  at  the  same  instant 
between  three  objects  furnish  one  of  the  most  accurate 
means  of  locating  the  position  of  a  vessel,  this  being 
the  same  method  that  is  ordinarily  used  in  hydrographic 
surveying,  known  as  the  three-point  problem.  (Fig.  44.) 
The  two  angles  are  conveniently  set  off  on  a  three-arm 
protractor,  which  is  shifted  on  the  chart  until  the  three 
arms  touch  the  three  points,  when  the  position  of  the 
center  is  plotted.  A  third  angle  to  a  fourth  point 
furnishes  a  valuable  check  in  case  of  doubt.  Two 
angles  may  also  be  taken  to  four  objects  without  any 
common  point,  and  in  this  case  portions  of  the  two 
circles  of  position  are  plotted  and  their  intersection 
will  be  the  ship's  position. 

The  value  of  this  method  depends  largely  on  the 
selection  of  favorably  located  objects,  and  it  is  quite 
important  that  the  principles  of  the  three-point  problem 


136  Use  of  Charts  in  Navigation 

be  understood.  If  the  ship  is  on  or  near  the  circum- 
ference of  a  circle  which  passes  through  the  three 
objects  the  position  will  be  very  weak,  and  the  same 
is  true  if  the  distance  between  any  two  of  the  objects 
is  small  as  compared  with  the  distance  from  them  to 
the  vessel.  A  useful  general  rule  is  that  the  position 
will  be  strong  if  the  middle  one  of  the  three  objects 
is  the  nearest  to  the  vessel,  provided  that  no  two  of 
the  objects  are  close  together  in  comparison  with  the 
distance  to  the  vessel. 

A  single  sextant  angle  furnishes  a  means  of  avoiding  a 
known  danger  by  using  what  is  known  as  the  horizontal 
"  danger  angle."  (Fig.  45.)  Note  two  well-defined  objects 
on  the  coast  either  side  of  the  danger  to  be  avoided  and 
describe  a  circle  through  them  and  passing  sufficiently 
outside  of  the  reef  to  give  it  a  safe  berth.  With  a  pro- 
tractor on  the  chart  note  the  angle  between  the  objects 
at  any  point  on  the  outer  part  of  this  circle.  If  in 
passing,  the  angle  at  the  ship  between  the  two  objects 
is  not  allowed  to  become  greater  than  this  "danger 
angle"  the  danger  will  be  given  a  sufficient  berth.  This 
method  as  well  as  any  use  of  sextant  angles  or  bearings 
depends  of  course  on  the  accuracy  of  the  chart,  and 
caution  must  be  used  where  it  is  not  certain  that  the 
chart  depends  upon  an  accurate  survey. 

Soundings.  Even  if  objects  cannot  be  seen,  due  to 
distance  or  thick  weather,  the  chart  furnishes  a  valuable 
aid  when  a  vessel  has  approached  within  the  limits 
where  it  is  practicable  to  obtain  soundings.  Modern 
navigational  sounding  machines  permit  of  obtaining 
soundings  to  depths  of  nearly  one  hundred  fathoms 
without  stopping  the  vessel.  A  rough  check  is  at  once 


Vertical  Angles  139 


obtained  by  comparing  such  soundings  with  those 
given  on  the  chart  for  the  position  carried  forward  by 
dead  reckoning.  If  a  number  of  soundings  are  taken 
and  plotted  on  a  piece  of  tracing  paper,  spaced  by  the 
log  readings  to  the  scale  of  the  chart,  and  this  tracing 
paper  is  laid  over  the  chart  and  shifted  in  the  vicinity 
of  the  probable  position  until  the  soundings  best  agree 
with  those  on  the  chart,  a  valuable  verification  of  posi- 
tion may  be  obtained.  This  is  particularly  the  case  if 
the  area  has  been  well  surveyed,  and  the  soundings 
taken  on  the  vessel  are  accurate,  and  the  configuration 
of  the  bottom  has  marked  characteristics.  For  instance, 
in  approaching  New  York  the  crossing  of  the  30,  20,  and 
10  fathom  curves  will  give  a  fair  warning  of  the  distance 
off  the  Long  Island  and  New  Jersey  coasts,  and  sound- 
ings across  such  a  feature  as  the  submerged  Hudson 
gorge  extending  to  the  southeastward  of  Sandy  Hook 
will  give  a  valuable  indication  of  position.  The  taking 
of  soundings  should  be  resorted  to  even  in  favorable 
conditions,  in  approaching  shoal  water,  as  a  check  on 
other  means  of  locating  the  vessel.  Many  marine 
disasters  are  attributed  to  failure  to  make  sufficient  use 
of  the  lead,  the  simplest  of  navigational  aids. 

Vertical  angles.  The  vertical  angle  of  elevation  of  an 
object  whose  height  is  known  will  give  the  distance,  and 
combined  with  a  bearing  or  other  information  this  per- 
mits of  locating  a  vessel  where  better  means  cannot  be 
used.  Distance  tables  are  published  for  this  method. 
(Fig.  46.)  The  vertical  angle  is  measured  with  a  sextant 
and  must  be  the  angle  at  the  ship  between  the  top  of  the 
object  and  the  sea  level  vertically  beneath  it;  for  a  hill 
or  mountain,  therefore,  the  eye  of  the  observer  should 


140  Use  of  Charts  in  Navigation 

be  near  the  water.  The  object  should  not  be  so  distant 
that  curvature  becomes  appreciable.  The  "vertical 
danger  angle"  is  a  means  of  avoiding  a  known  danger, 
on  a  principle  similar  to  that  of  the  horizontal  danger 
angle;  that  is,  the  angle  of  elevation  of  a  known  object 
is  not  permitted  to  become  greater  than  a  fixed  amount 
depending  on  the  distance  from  the  object  to  the  danger 
to  be  avoided. 

Positions  by  sound.  In  thick  weather  sound  affords 
a  valuable  aid  to  the  navigator.  In  narrow  passages 
noting  the  echo  of  the  whistle  from  a  cliff  is  a  method 
resorted  to,  as  for  instance  in  Puget  Sound  and  along 
the  Alaska  coast.  Fog  whistles  and  bell  buoys  are 
maintained  at  many  places.  Submarine  bells  have 
recently  been  introduced  at  a  number  of  points  along 
the  Atlantic  coast,  and  vessels  may  be  equipped  to  receive 
these  submarine  signals  transmitted  through  the  water, 
which  indicate  also  the  general  direction  from  which 
the  sound  comes. 

Need  of  vigilance.  Too  great  importance  cannot  be 
attached  to  frequent  verification  of  positions  by  the  best 
available  means,  particularly  when  approaching  the 
land.  Neglect  of  this  or  overconfidence  has  caused 
many  disasters.  A  notable  instance  was  the  loss  of  one 
of  the  largest  Pacific  steamers  on  the  coast  of  Japan  in 
March,  1907.  In  the  afternoon  of  a  clear  day  this 
vessel  ran  on  to  a  well-known  reef  about  a  mile  from  a 
lighthouse,  resulting  in  the  total  loss  of  vessel  and  cargo 
valued  at  three  and  a  half  million  dollars.  The  captain 
was  so  confident  of  his  position  and  that  he  was  giving 
the  reef  a  sufficient  berth  that  he  laid  down  no  bearings 
on  the  chart  and  took  no  soundings. 


FIG.  47.     FIELD'S  PROTRACTOR   AND  PARALLEL  RULER   IN   USE  ON   A  CHART, 
PLOTTING    BEARING   OF  A   LIGHTHOUSE. 


(141; 


Instruments  143 


Instruments.  The  principal  instruments  needed  for 
use  with  charts  are ;  dividers  for  taking  off  distances  and 
latitudes  and  longitudes,  parallel  ruler  for  transferring 
directions  to  or  from  a  compass  rose  and  for  taking  off 
or  plotting  the  latitude  on  a  mercator  chart,  protractor  of 
180  degrees  for  reading  the  angle  with  the  meridian  of  any 
direction  or  for  laying  off  on  the  chart  any  given  angle  with 
the  meridian,  and  three-arm  or  other  full-circle  protrac- 
tor for  plotting  a  position  by  the  three-point  problem. 

Parallel  rulers  on  the  principle  of  Field's  are  strongly 
recommended  for  chart  work,  as  they  combine  in  a 
single  instrument  the  advantages  of  a  parallel  ruler 
and  a  180-degree  protractor.  Any  direction  can  be 
read  or  laid  off  by  simply  moving  the  parallel  ruler 
to  the  nearest  projection  line,  which  is  a  process  not 
only  more  convenient  than  referring  to  the  compass 
rose  printed  on  the  chart  but  also  more  accurate 
because  of  the  longer  radius.  These  instruments 
can  also  be  used  the  same  as  a  plain  parallel  ruler. 
Field's  parallel  rulers  are  made  in  two  forms,  one  rolling 
and  the  other  sliding.  The  former  is  a  single  ruler  > 
with  edge  graduated  90  degrees  either  way,  and 
mounted  on  rollers;  it  is  the  most  rapid  instrument 
for  reading  or  laying  off  a  direction,  but  it  requires 
a  smooth  surface.  The  latter  is  an  ordinary  two- 
bar  parallel  ruler  with  edge  when  closed  graduated 
90  degrees  either  way;  it  is  a  very  serviceable  instrument 
and  probably  more  to  be  depended  upon  for  ordinary 
use  than  the  rolling  form.  Some  form  of  combined 
protractor  and  parallel  ruler  should  be  in  every  navi- 
gational equipment,  and  it  is  unfortunate  that  these 
instruments  are  not  better  known  in  this  country. 


144  Use  of  Charts  in  Navigation 

There  are  other  forms  of  half-circle  protractors  which 
are  used  on  the  same  principle,  that  is,  of  bringing 
the  center  on  to  a  projection  line  and  reading  where 
the  line  cuts  the  border  graduation  of  the  protractor. 
Thus  a  semicircular  protractor  is  used  with  a  separate 
straight  edge,  along  which  it  is  slid  to  the  nearest 
meridian;  another  form  is  the  simple  circular  pro- 
tractor with  a  thread  fastened  at  the  center.  All  these 
forms  of  protractors,  it  will  be  noted,  are  intended  to 
work  from  the  true  meridian,  and  they  are  usually 
graduated  in  degrees  only;  the  use  of  degrees  instead 
of  points  is  becoming  much  more  general  in  navigational 
work,  and  reference  to  the  true  meridian  is  also  more 
common  than  formerly. 

The  standard  three-arm  protractor,  or  station 
pointer,  as  it  is  known  to  the  English,  should  be  a  part 
of  every  navigational  outfit  because  of  its  value  in 
locating  a  position  by  the  three-point  problem.  A 
recent  American  invention,  Court's  three-arm  pro- 
tractor, is  an  instrument  made  of  celluloid  for  the 
same  purpose.  It  should  not  be  considered  as  a 
substitute  for  the  standard  metal  instrument,  but  it 
is  a  simple,  cheap,  and  handy  supplement  to  it,  as  it 
may  be  readily  used  for  small  angles  and  short  dis- 
tances where  there  are  mechanical  difficulties  in  work- 
ing with  the  metal  three-arm  protractor.  Other  pro- 
tractors can  be  used  for  the  three-point  problem,  as,  for 
instance,  Gust's  protractor  on  celluloid,  on  which  the 
angles  are  drawn  in  pencil  and  erased,  and  the  tracing- 
paper  protractor. 

Degree  of  reliance  on  charts.  The  value  of  a  chart 
must  not  be  judged  alone  from  its  general  appearance, 


FIG.  48.     THREE-ARM    PROTRACTOR  IN    USE   ON   A  CHART,  PLOTTING   POSITION    FROM 

TWO  ANGLES, 


(145) 


Degree  of  Reliance  147 

as  skill  in  preparation  and  publication  may  give  a 
handsome  appearance  to  an  incomplete  survey.  On 
the  other  hand  a  thorough  survey  might  through  poor 
preparation  result  in  a  chart  defective  either  in  infor- 
mation or  in  utility. 

The  degree  of  completeness  of  the  soundings,  the 
character  of  the  region,  and  the  date  of  the  survey 
should  be  taken  into  account  in  deciding  as  to  the 
amount  of  reliance  to  be  placed  on  the  chart.  Areas 
where  the  soundings  are  not  distributed  with  fair 
uniformity  may  be  assumed  not  to  have  been  completely 
surveyed.  Caution  should  be  used  in  navigating  on 
charts  where  the  survey  is  not  complete,  and  even  where 
careful  surveys  exist  care  must  be  taken  if  the  bottom 
is  of  very  irregular  nature  with  lumps  near  the  navi- 
gable depth,  as  for  instance  on  some  of  the  coral 
reef  coasts.  Isolated  soundings  shoaler  than  the  sur- 
rounding depths  should  be  avoided,  as  there  may  be 
less  water  than  shown.  In  such  a  region,  unless  the 
whole  area  is  dragged,  it  is  impossible  to  make  it 
entirely  certain  that  all  obstructions  are  charted. 

While  an  immense  amount  of  faithful  work  has 
been  put  into  the  preparation  of  many  charts,  the 
user  must  constantly  exercise  his  own  judgment  as  to 
the  reliance  to  be  placed  on  them.  A  coast  is  not 
to  be  considered  as  clear  unless  it  is  shown  to  be;  buoys 
may  get  adrift  and  be  in  a  different  position  or  be 
gone  altogether;  fog  signals  vary  in  distinctness  owing 
to  atmospheric  conditions;  extreme  or  unusual  tides 
may  fall  below  the  plane  of  reference;  owing  to  strong 
winds  the  actual  tide  may  differ  from  the  predicted 
tide.  Errors  sometimes  creep  in  from  various  sources, 


148  Use  of  Charts  in  Navigation 

such  as  those  due  to  different  reference  longitudes 
or  the  use  of  a  corrected  longitude  for  a  portion  of  the 
chart  without  changing  other  positions  to  which  the 
same  correction  is  applicable;  clerical  and  printing 
errors  may  occur;  there  are  sometimes  omissions  in 
surveys;  a  feature  may  get  plotted  in  two  different 
positions;  tide  rips  are  reported  as  breakers  and 
floating  objects  as  rocks  or  islands,  and  thus  many 
dangers  have  gotten  on  the  charts  which  cannot  be 
found  again,  and  false  reports  are  sometimes  made  to 
shield  some  one  from  blame.  Most  of  these  classes 
of  errors  and  uncertainties,  however,  disappear  in  the 
use  of  charts  of  a  thoroughly  surveyed  coast. 

Use  the  latest  editions  of  charts.  The  latest  edition 
of  a  chart  should  always  be  used  and  should  be  corrected 
for  all  notices  since  its  issue.  Carelessness  or  false 
economy  in  not  providing  the  largest  scale  or  the  latest 
chart  has  been  the  cause  of  more  than  one  marine 
disaster. 

The  British  Board  of  Trade  issue  the  following 
official  notice  to  shipowners  and  agents:  "The  attention 
of  the  Board  of  Trade  has  frequently  been  called  to 
cases  in  which  British  vessels  have  been  endangered  or 
wrecked  through  the  masters'  attempting  to  navigate 
them  by  means  of  antiquated  or  otherwise  defective 
charts.  The  Board  of  Trade  desires,  therefore,  to 
direct  the  especial  attention  of  shipowners  and  their 
agents  to  the  necessity  of  seeing  that  the  charts  taken  or 
sent  on  board  their  ships  are  corrected  to  the  time  of 
sailing.  Neglect  to  supply  a  ship  with  proper  charts 
will  be  brought  prominently  before  the  Court  of  Inquiry 
in  the  event  of  a  wreck  occurring  from  that  cause." 


Use  Latest  Editions  149 

The  following  is  a  translation  of  a  notice  in  the 
preface  to  the  catalogue  of  charts  published  by  the 
German  government:  "Owners  and  masters  of  vessels 
are  apprised  that  cases  of  marine  accidents  in  which  the 
casualty  was  due  to  antiquated  or  erroneous  charts, 
have  frequently  been  before  the  admiralty  courts.  In 
consequence  of  this,  the  '  Instructions  for  the  prevention 
of  accidents  to  steamers  and  sailing  vessels,'  issued  by 
the  Seeberufsgenossenschaft  have  been  amended  by  the 
following  additional  paragraph:  'It  is  obligatory  upon 
every  master,  except  when  engaged  in  local  coastwise 
navigation,  to  keep  the  Notices  to  Mariners  regularly, 
and  with  the  aid  of  them  to  carefully  keep  his  charts 
up  to  date.'" 

The  British  shipping  laws  provide  that  a  ship  may 
not  be  sent  to  sea  in  such  an  unseaworthy  state  that  the 
life  of  any  person  is  thereby  endangered,  and  the  House 
of  Lords  has  defined  the  term  "seaworthy"  to  mean  "in 
a  fit  state  as  to  repairs,  equipment,  and  crew,  and  in  all 
other  respects,  to  encounter  the  ordinary  perils  of  the 
voyage."  Proper  charts  and  sailing  directions  are  a 
necessary  part  of  the  equipment  of  a  vessel,  and  the 
courts  have  frequently  inquired  into  this. 

The  records  of  the  British  courts,  however,  show  that 
even  in  recent  years  many  ships  have  been  damaged 
or  lost  owing  directly  or  indirectly  to  failure  to  have 
the  latest  information  on  board.  The  following  are 
instances  from  these  records. 

In  1890  the  steamer  Dunluce  was  lost  owing  to  the 
use  of  an  old  edition  of  the  Admiralty  chart  which 
showed  a  depth  of  4^  fathoms  on  the  Wikesgrund, 
whereas  the  later  chart  showed  much  less  water.  In 


150  Use  of  Charts  in  Navigation 

this  case  the  master  had  requested  his  ship  chandler  to 
send  him  the  latest  chart. 

In  1891  the  steamer  St.  Donats  got  ashore  on  a 
patch  which  was  not  shown  on  the  chart  in  use,  which 
was  privately  published  in  1881 ;  the  danger  was,  how- 
ever, shown  on  the  Admiralty  chart  corrected  to  1889. 

Also  in  1891  the  steamer-  Trent  was  lost  on  the 
Missipezza  Rock  in  the  Adriatic.  The  ship  was  navi- 
gated by  a  private  chart  published  in  1890  which  did 
not  show  this  rock,  and  by  sailing  directions  published 
in  1866. 

The  steamer  Aboraca,  stranded  in  the  Gulf  of 
Bothnia  in  1894,  was  being  navigated  by  a  chart  cor- 
rected to  1881  which  did  not  show  that  the  Storkalla- 
grund  light- vessel  had  been  moved  eight  miles. 

The  steamer  Ravenspur  was  lost  on  Bilbao  Break- 
water owing  to  the  use  of  a  chart  not  up  to  date  which 
did  not  show  the  breakwater.  In  1898  the  steamer 
Cromarty  was  lost  in  attempting  to  enter  Ponta 
Delgada  harbor,  and  in  1901  the  steamer  "Dinning- 
ton"  was  lost  by  steaming  on  to  the  new  breakwater  in 
Portland  harbor;  both  of  these  disasters  were  likewise 
due  to  the  use  of  old  charts  which  did  not  show  the 
breakwaters.  In  these  three  cases  the  masters  of  the 
vessels  had  authority  to  obtain  the  necessary  charts  at 
the  owners'  expense. 

Not  so,  however,  in  the  following  case  from  the 
finding  of  a  British  marine  court  in  1877:  "The  primary 
cause  of  the  ship's  getting  on  shore  was  due  to  the 
master's  being  guided  in  his  navigation  by  an  obsolete 
Admiralty  chart  dated  September  1,  1852,  and  cor- 
rected to  April,  1862,  and  on  which  no  lights  are  shown 


Use  Largest  Scale  Charts  151 

to  exist  either  in  ...  or  ...  and  to  his  not  being 
supplied  with  the  latest  sailing  directions.  The  Court, 
considering  that  the  master  was  obliged  to  furnish 
himself  with  chronometer,  barometer,  sextant,  charts, 
sailing  directions,  and  everything  necessary  for  the 
navigation  of  his  vessel  out  of  his  private  resources, 
which,  under  very  favorable  circumstances,  might  per- 
haps reach  .£150  a  year,  find  themselves  unable  in  this 
instance  to  pass  a  heavier  censure  upon  him  than  that 
he  be  severely  reprimanded." 

The  loss  of  the  German  steamer  Baker  on  the  coast 
of  Cuba  on  January  31,  1908,  was  declared  by  the 
marine  court  at  Hamburg  to  be  due  in  part  to  the  use 
of  an  unofficial  chart  which  did  not  show  the  latest 
surveys  on  that  coast. 

Use  the  largest  scale  charts.  The  largest  scale  chart 
available  should  be  employed  when  entering  channels, 
bays,  or  harbors,  as'  it  gives  information  with  more 
clearness  and  detail,  positions  may  be  more  accurately 
plotted,  and  sometimes  it  is  the  first  corrected  for  new 
information. 

The  records  of  the  courts  of  inquiry  also  show 
cases  where  vessels  have  been  wrecked  owing  to  the  use 
of  charts  of  too  small  scale. 

In  1890  the  steamer  Lady  Ailsa  was  lost  on  the 
Plateau  du  Four.  The  only  chart  on  board  for  this 
locality  was  a  general  chart  of  the  Bay  of  Biscay, 
and  the  stranding  was  due  to  the  master's  mistaking 
one  buoy  for  another.  The  court  found  that  the 
chart,  although  a  proper  one  for  general  use,  was  not 
sufficient  for  the  navigation  of  a  vessel  in  such  narrow 
waters  and  on  such  a  dangerous  coast. 


152  Use  of  Charts  in  Navigation 

The  Zenobia  was  stranded  on  the  San  Thome 
Bank  in  1891.  On  this  vessel  the  owners  were  to 
furnish  the  chronometers  and  the  master  the  charts 
and  sailing  directions.  The  master  was,  however, 
apparently  satisfied  with  only  a  general  chart  of  the 
South  Atlantic  for  navigation  on  the  coast  of  Brazil, 
and  had  no  sailing  directions  at  all. 

The  depth  curves  on  charts  furnish  a  valuable  guide, 
and  if  the  curves  are  lacking  or  broken  in  some  parts 
it  is  usually  a  sign  that  the  information  is  incomplete. 
The  100-fathom  curve  is  a  general  warning  of  approach 
to  the  coast.  The  10-fathom  curve  on  rocky  coasts 
should  be  considered  as  a  danger  curve,  and  caution 
used  after  crossing  it.  The  5-fathom  curve  is  the 
most  important  for  modern  vessels  of  medium  draft, 
as  it  indicates  for  them  the  practical  limit  of  naviga- 
tion. The  3,  2,  and  1-fathom  curves  are  a  guide  to 
smaller  vessels,  but  have  less  significance  than  formerly 
because  of  the  increase  of -draft  of  vessels. 

The  shrinkage  of  paper,  especially  in  plate  printing, 
has  been  referred  to.  This  introduces  two  possible 
sources  of  error:  first,  the  shrinkage  being  different 
in  the  two  directions,  any  scale  printed  on  the  chart 
will  be  accurate  only  when  used  in  a  direction  parallel 
to  itself;  second,  for  the  same  reason,  angles  and 
directions  will  be  somewhat  distorted.  Fortunately 
these  errors  are  not  serious  in  the  ordinary  navigational 
use  of  a  chart,  but  they  should  not  be  overlooked  when 
accurate  plotting  or  measuring  of  distances  is  attempted 
on  a  plate-printed  chart. 

The  actual  shrinkage  measured  on  charts  printed 
from  plates  varies  from  ^  inch  to  1  inch  in  a  length 


Care  of  Charts  153 


of  chart  of  36  inches.  On  British  and  American  plate 
printed  charts  the  shrinkage  is  usually  from  two  to 
nearly  three  times  as  much  in  one  direction  as  it  is  in 
the  other. 

Care  of  charts.  In  order  that  they  may  be  properly 
used  charts  should  be  filed  flat  and  not  rolled.  They 
should  be  systematically  arranged  so  that  the  desired 
chart  can  be  instantly  found.  They  should  be  cared 
for  and  when  in  bad  condition  replaced  by  new  copies. 
They  can  be  most  conveniently  filed  in  shallow  drawers, 
thus  avoiding  the  placing  of  many  charts  in  a  single 
drawer.  The  latter  is  a  common  fault;  it  not  only 
increases  the  labor  of  handling  the  charts  but  adds 
to  the  liability  of  their  injury. 


PUBLICATIONS   SUPPLEMENTING  NAUTICAL 
CHARTS. 

There  are  several  publications  in  book  and  in  chart 
form  which  are  either  necessary  or  convenient  for  use 
in  connection  with  nautical  charts.  These  comprise 
the  coast  pilots,  notices  to  mariners,  tide  tables,  light 
and  buoy  lists,  and  various  special  charts. 

Coast  pilots,  or  sailing  directions,  are  books  giving 
descriptions  of  the  main  features,  as  far  as  of  interest 
to  seamen,  of  the  coast  and  adjacent  waters,  with 
directions  for  navigation.  They  contain  much  miscel- 
laneous information  of  value  to  the  mariner,  especially 
the  stranger.  Although  they  contain  additional  facts 
which  cannot  be  shown  on  the  charts,  they  are  not  at 
all  intended  to  supersede  the  latter;  the  mariner  should 
in  general  rely  on  the  charts.  The  sailing  directions 
can  be  less  readily  corrected  than  the  charts,  and  in  all 
cases  where  they  differ  the  charts  are  to  be  taken  as  the 
guide. 

The  most  extensive  series  of  sailing  directions  is 
that  published  by  the  British  Admiralty,  comprising 
fifty-six  volumes  and  including  all  the  navigable  regions 
of  the  world.  In  the  United  States  the  Coast  and 
Geodetic  Survey  publishes  ten  volumes  of  coast  pilots 
for  the  Atlantic,  Gulf,  and  Pacific  coasts,  Porto  Rico, 
and  southeastern  Alaska,  and  eight  volumes  of  sailing 
directions  for  Alaska  and  the  Philippine  Islands. 
The  United  States  Hydrographic  Office  publishes  six- 

154 


Notices  to  Mariners  155 

teen  volumes  of  sailing  directions  for  various  parts  of 
the  world. 

Notices  to  Mariners  are  published  at  frequent  inter- 
vals, giving  all  important  corrections,  which  should  be 
at  once  applied  by  hand  to  the  charts,  such  as  rocks 
or  shoals  discovered  and  lights  and  buoys  established 
or  moved.  New  charts,  new  editions,  and  canceled 
charts  are  also  announced. 

These  notices  should  be  carefully  examined  and  the 
necessary  corrections  made  on  all  charts  of  the  sets  in 
use  on  the  vessel.  A  chart  should  be  considered  as  a 
growing  rather  than  a  finished  instrument,  and  constant 
watchfulness  is  required  to  see  that  it  is  kept  up  to 
date.  Neglect  of  this  may  cause  shipwreck,  as  the  fol- 
lowing instance  shows.  Report  came  to  Manila  in 
1904  that  there  was  a  low  sand  islet  lying  off  the  very 
poorly  charted  northeast  coast  of  Samar;  this  infor- 
mation was  promptly  published  in  the  local  Notice  to 
Mariners.  About  a  month  later  a  small  steamer  was 
sent  to  land  some  native  constabulary  on  that  coast. 
The  captain  failed  to  obtain  or  observe  this  notice, 
and  approached  the  coast  before  daylight  on  a  course  . 
which  led  directly  across  the  sand  islet.  The  vessel 
was  driven  far  up  on  the  sand,  where  it  still  lies. 

In  the  United  States,  weekly  Notices  to  Mariners 
are  published  by  the  Department  of  Commerce  and 
Labor  for  the  coasts  under  the  jurisdiction  of  the 
United  States,  and  by  the  Navy  Department  for  all 
regions.  These  notices  are  distributed  free  and  can 
be  obtained  from  chart  agents  and  consular  officers. 
In  Great  Britain  the  notices  are  published  at  frequent 
intervals  by  the  Hydrographic  Office,  and  practically 


156  Supplementary  Publications 

all  countries  issuing  charts  also  issue  such  notices. 
Information  as  to  important  changes  in  lights  and 
other  announcements  of  navigational  interest  are  also 
sometimes  printed  in  the  marine  columns  of  news- 
papers and  in  nautical  periodicals. 

Tide  Tables.  Brief  information  as  to  the  time  and 
height  of  the  tide  is  usually  for  convenience  given  on 
the  face  of  the  chart.  More  complete  information  is 
published  in  the  Tide  Tables,  with  which  every  navi- 
gator should  be  provided.  "The  Tide  Tables  for 
United  States  and  foreign  ports/'  published  annually 
in  advance  by  the  United  States  Coast  and  Geodetic 
Survey,  give  complete  predictions  of  the  time  and 
height  of  high  and  low  water  for  each  day  of  the  year 
for  70  of  the  principal  ports  of  the  world,  and  the  tidal 
differences  from  some  principal  port  for  3000  subordi- 
nate ports.  The  other  leading  nations  also  publish 
annual  tide  tables;  those  of  the  British  government 
are  entitled  "  Tide  Tables  for  British  and  Irish  ports, 
and  also  the  times  of  high  water  for  the  principal 
places  on  the  globe." 

Light  and  buoy  lists.  Brief  information  as  to  all 
artificial  aids  to  navigation  is  shown  on  the  charts. 
Every  vessel  should  also  have  on  board  the  latest 
official  light  and  buoy  lists,  which  give  a  more  detailed 
description  than  can  be  placed  on  the  charts. 

Light  and  buoy  lists  for  the  coasts  of  the  United  States 
are  published  annually  by  the  Light-House  Board. 
The  United  States  Hydrographic  Office  publishes  a 
"List  of  Lights  of  the  World"  (excepting  the  United 
States) ,  in  three  volumes. 

The    British    Hydrographic    Office    publishes    eight 


Chart  Catalogues  157 


volumes  of  Lists  of  Lights,  and  these  are  corrected 
annually. 

Chart  catalogues  are  published  in  connection  with 
all  series  of  charts.  They  give  the  particulars  and 
price  of  each  chart  published,  and  are  usually  arranged 
in  geographical  order,  with  both  alphabetical  and 
numerical  indexes,  for  convenience  in  rinding  charts 
either  by  position,  name,  or  number. 

Charts  for  special  purposes.  There  are  various 
special  charts  published  for  the  benefit  of  mariners, 
although  not  intended  for  direct  use  in  plotting  the 
course  of  a  vessel  or  in  locating  its  position.  Some 
of  the  more  important  of  these  are  mentioned  below. 

Gnomonic  charts  are  intended  solely  for  laying  down 
the  great  circle  or  shortest  practicable  courses  between 
points,  for  which  purpose  they  are  very  convenient. 
Their  use  has  already  been  described.  The  United 
States  Hydrographic  Office  publishes  six  such  charts, 
for  the  North  Atlantic,  South  Atlantic,  Pacific,  North 
Pacific,  South  Pacific,  and  Indian  Oceans. 

Current  charts  are  published  by  the  British  Hydro- 
graphic  Office  for  the  various  oceans;  these  usually 
show  the  average  ocean  currents,  but  for  the  Atlantic 
there  are  monthly  and  for  the  Pacific  quarterly  current 
charts. 

Magnetic  variation  charts  are  published  by  both  the 
United  States  and  British  governments.  They  show 
on  a  mercator  chart  of  the  world  the  isogonic  lines, 
or  lines  along  which  the  variation  of  the  needle  from 
true  north  is  the  same.  The  lines  are  drawn  for  each 
degree  of  variation.  The  annual  change  in  the  varia- 
tion is  also  indicated. 


158  Supplementary  Publications 

Other  magnetic  charts  are  published  showing  the 
lines  of  equal  magnetic  dip,  horizontal  magnetic  force, 
and  vertical  magnetic  force. 

Meteorological  ocean  charts  are  published  by  sev- 
eral governments,  including  the  United  States,  Great 
Britain,  and  Germany,  and  give  the  average  weather 
conditions,  winds,  fogs,  currents,  ice,  tracks  of  storms, 
and  other  information.  "Pilot  charts "  of  the  North 
Atlantic  and  North  Pacific  Oceans  are  issued  by  the 
United  States  Hydrographic  Office  about  the  first  of 
each  month,  and  give  "a  forecast  of  the  weather  for  the 
ensuing  and  a  review  of  that  for  the  preceding  month, 
together  with  all  obtainable  information  as  to  the  most 
available  sailing  and  steam  routes,  dangers  to  navigation, 
ice,  fog,  derelicts,  etc.,  and  any  additional  information 
that  may  be  received  of  value  to  navigation."  Mariners 
in  all  parts  of  the  world  have  joined  in  contributing 
the  information  which  has  been  used  in  compiling 
these  pilot  charts. 

Track  charts  are  published  by  the  British  and 
United  States  governments.  That  of  the  latter  is 
entitled  "  Track  and  distance  chart  of  the  world,  show- 
ing the  routes  traversed  by  full-powered  steamers 
between  the  principal  ports  of  the  world,  and  the 
corresponding  distances." 

Telegraph  charts  are  published  showing  the  "  tele- 
graphic connections  afforded  by  the  submarine  cables 
and  the  principal  overland  telegraph  lines." 

Index  charts  are  outline  plans  showing  the  area 
covered  by  each  chart  of  a  series,  and  furnish  a  con- 
venient means  of  finding  a  chart  of  any  desired  region 
or  of  selecting  the  most  suitable  chart  for  any  purpose. 


Star  Charts  159 


These  index  charts  are  published  either  in  sets,  showing 
all  the  charts  of  a  series,  or  are  bound  into  the  chart 
catalogues. 

Star  charts  are  included  in  navigational  series, 
and  are  conveniently  arranged  for  use  on  shipboard 
in  identifying  the  brighter  stars.  The  United  States 
Hydrographic  Office  publishes  two,  constellations  of 
the  northern  and  of  the  southern  hemispheres. 

Explanatory  sheets  are  published  in  connection 
with  various  series  of  charts,  giving  explanations  of 
the  symbols  and  abbreviations  used  and  of  other 
important  features.  In  the  United  States  the  Coast 
and  Geodetic  Survey  has  issued  a  small  pamphlet, 
"Notes  on  the  use  of  charts,"  which  contains  explana- 
tions of  its  chart  symbols,  and  the  Hydrographic  Office 
has  published  "  A  manual  of  conventional  symbols  and 
abbreviations  in  use  on  the  official  charts  of  the  principal 
maritime  nations." 


INDEX 


Aids  to  navigation 118 

Arbitrary  projection 79 

Astronomical  observations 32 

Astronomical  positions 126 


Bearings,  position  by 130 

Board  of  Trade  notice 148 

Care  of  charts 153 

Catalogues  of  charts 157 

Changes  in  the  coast 98 

Chart  making,  development  of. ...  6 
Chart  publications  of  various 

nations 18 

Charts,  earliest  nautical 6 

Charts,  loxodromic 7 

Charts,  plain 8 

Chart  schemes 67 

Chart  working 124 

Coast  and  Geodetic  Survey,  United 

States 13 

Coast  pilots 154 

Compass  bearings 130 

Compass,  nautical  use  of 6 

Compass,  variation  of 7 

Compilation  of  information 67 

Correction  of  charts,  method  of.  ...  110 

Cosa,  Juan  de  la 8 

Current  charts 157 

Currents 50,  121 

Danger  angle,  horizontal 136 

Danger  bearing 131 

Danger  range 132 

Dangers,  reports  of 56 

Dates  on  charts 123 

Dead  reckoning 129 


PAGE  PAGE 

Depth  curves 116,  152 

Depths,  unit  for 19,  116 

Depth  units,  relation  of 118 

Directions  on  charts 115 

Distances,  measured  on  chart 125 

Distribution  of  charts 96 

Doubling  angle  on  bow 131 

Draft  of  vessels 97 

Dragging  for  dangers 55 

Earthquakes 109 

Electrotyping  plates 89 

Elevations 122 

Engraving  machines 89 

Engraving  on  copper 84 

Engraving  on  stone 93 

Eskimo  map 1 

Etching  on  copper 95 

Explanatory  sheets 159 

Flattening  of  the  earth 3 

France,  establishment  of  chart  office     10 

Geographic  position  on  charts 115 

Geography,  early 2 

Germany,  contributions  to  hydrog- 
raphy   14 

Gnomonic  charts 79,  157 

Gnomonic  projection 74 

Great    Britain,     contributions     to 

geography 14 

Holland,    development    of    chart 

making 10 

Hydrographic  Office,  British 13 

Hydrographic  Office,  United  States  13 

Hydrography 40 


161 


162 


Index 


PAGE 

Index  charts 158 

Information  on  charts 23 

Instruments  used  on  charts 141 

Lake  Survey,  United  States 13 

Largest  scale  chart 151 

Latest  editions  of  charts 148 

Light  and  buoy  lists 156 

Lithographic  printing 94 

Locating  a  vessel 126 

Longitude,  initial 19 

Longitude,  uncertainties  in 10 

Magnetic  charts 157 

Magnetic  variation 56 

Map,  earliest 2 

Map  making,  development  of 2 

Maps,  need  of 1 

Maritime  surveys,  extension  of 17 

Mercator  chart,  history 8 

Mercator  projection 68 

Meteorological  charts  (pilot  charts)  158 

Navigation,  use  of  charts  in 124 

Notices  to  mariners „ Ill,  155 

Paper,  shrinkage  of 152 

Parallel  rulers,  Field's 141 

Photolithography 93 

Plane  of  reference 20,  1 19 

Plotting  positions 124 

Polyconic  projection 73 

Printing,  plate 84,  90 

Privately  published  charts 21 

Progress  of  hydrographic  surveys. .      17 

Projection,  explanation  of 114 

Projections 68,  114 

Protractor,  three-arm 144 

Ptolemy 3 

Publication  of  charts,  methods 84 

Purpose  of  charts 22 


132 


PAGE 

Reliance  on  charts 144 

Reports  of  dangers,  erroneous 57 

Requirements  for  charts 23 

Revision  of  charts,  need  of 97 

Rock,  Brooklyn 50 

Sailing  directions,  early 4 

Sailing  directions 154 

Scale  equivalents 113 

Scales  of  charts 79,  112 

Set,  graphical  allowance  for 125 

Sextant  angles 132 

Sheets  for  surveys 39 

Shrinkage  of  paper 152 

Sound,  position  by 140 

Sounding  machines 49 

Soundings,  position  by 136 

Star  charts 159 

Station  pointer x 144 

Steamer  for  surveying 49 

Simmer's  method 126 

Supplementary  publications 154 

Surveys  on  foreign  coasts 14 

Surveys,  need  of  thorough 31 

Symbols  on  charts 20 

Telegraph  charts 158 

Three-point  problem 132,  135 

Tides 50,  120 

Tide  tables 156 

Topography 39 

Topography  on  charts 123 

Track  charts 158 

Triangulation 32 

Uniformity  in  charts 21 

Use  of  charts  in  navigation 124 

Vertical  angles 139 

Vigias,  removal  of 62 

Vigilance,  need  of 140 

Volcanic  action. . .  .109 


Reading  charts 112       Wrecks  due  to  deficient  charts 149 


SHORT-TITLE     CATALOGUE 

OP  THE 

PUBLICATIONS 

JOHN   WILEY   &   SONS, 

NEW  YORK. 
LONDON:   CHAPMAN  &  HALL,  LIMITED. 


ARRANGED  UNDER  SUBJECTS. 


Descriptive  circulars  sent  on  application.      Books  marked  with   an  asterisk  (*)  are  sold 
at   net  prices   only.       All  books  are  bound  in  cloth  unless  otherwise  stated. 


AGRICULTURE. 

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Principles  of  Animal  Nutrition 8vo,  4  oo 

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Graves's  Forest  Mensuration 8vo,  4  oo 

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*  McKay  and  Lar sen's  Principles  and  Practice  of  Butter-making 8vo,  i  50 

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1 2 mo,  morocco,  r  50 

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Lodge's  Notes  on  Assaying  and  Metallurgical  Laboratory  Experiments.  .  .  .8vo,  3  oo. 

Low's  Technical  Methods  of  Ore  Analysis 8vo,  3  oo. 

Miller's  Manual  of  Assaying i2mo,  i  oo. 

Cyanide  Process i2mo,  i  oo, 

Minet's  Production  of  Aluminum  and  its  Industrial  Use.     (Waldo.) i2mo,  2  50, 

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Robine  and  Lenglen's  Cyanide  Industry.     (Le  Clerc.) 8vo,  4  oo 

Ulke's  Modern  Electrolytic  Copper  Refining 8vo,  3  oo 

Wilson's  Cyanide  Processes I2mo,  i  50 

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Craig's  Azimuth 4to,  3  50 

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3 


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1 6mo,  morocco,  i  25 

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Adriance's  Laboratory  Calculations  and  Specific  Gravity  Tables i2mo,  i  25 

Alexeyeff's  General  Principles  of  Organic  Synthesis.     (Matthews.) 8vo,  3  oo 

.Allen's  Tables  for  Iron  Analysis 8vo,  3  oo 

.Arnold's  Compendium  of  Chemistry.     (Mandel.) Small  8vo,  3  50 

Austen's  Notes  for  Chemical  Students i2mo,  i  50 

Beard's  Mine  Gases  and  Explosions.     (In  Press.) 

Bernadou's  Smokeless  Powder. — Nitre-cellulose,  and  Theory  of  the  Cellulose 

Molecule i2mo,  2  50 

Bolduan's  Immune  Sera I2mo,  i  50 

*  Browning's  Introduction  to  the  Rarer  Elements 8vo,  i  50 

Brush  and  Penfield's  Manual  of  Determinative  Mineralogy 8vo,  4  oo 

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Classen's  Quantitative  Chemical  Analysis  by  Electrolysis.    (Boltwood.).  .8vo,  3  oo 

Cohn's  Indicators  and  Test-papers i2mo,  2  oo 

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Crafts's  Short  Course  in  Qualitative  Chemical  Analysis.   (Schaeffer.). .  .i2mo,  i  50 

*  Danneel's  Electrochemistry.     (Merriam.) I2mo,  i   25 

Dolezalek's   Theory  of  the   Lead  Accumulator   (Storage   Battery).        (Von 

Ende.) i2mo,  2  50 

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Duhem's  Thermodynamics  and  Chemistry.     (Burgess.) 8vo,  4  oo 

Eissler's  Modern  High  Explosives 8vo,  4  oo 

Effront's  Enzymes  and  their  Applications.     (Prescott.) 8vo,  3  oo 

Erdmann's  Introduction  to  Chemical  Preparations.     (Dunlap.) i2mo,  i  25 

*  Fischer's  Physiology  of  Alimentation Large  I2mo,  2  oo 

Fletcher's  Practical  Instructions  in  Quantitative  Assaying  with  the  Blowpipe. 

i2mo,  morocco,  i  50 

Fowler's  Sewage  Works  Analyses i2mo,  2  oo 

Fresenius's  Manual  of  Qualitative  Chemical  Analysis.     (Wells.) 8vo,  5  oo 

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Quantitative  Chemical  Analysis.     (Cohn.)     2  vols 8vo,  12  50 

Fuertes's  Water  and  Public  Health i2mo,  i  50 

Furman's  Manual  of  Practical  Assaying 8vo,  3  oo 

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Grotenfelt's  Principles  of  Modern  Dairy  Practice.     (Woll.) i2mo,  2  oo 

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Hanausek's  Microscopy  of  Technical  Products.     (Winton. ) 8vo,  5  oo 

*  HasMn's  and  MacLeod's  Organic  Chemistry 12mo,  2  oo 

Helm's  Principles  of  Mathematical  Chemistry.     (Morgan.) i2mo,  i  50 

Bering's  Ready  Reference  Tables  (Conversion  Factors) i6mo,  morocco,  2  50 

Herrick's  Denatured  or  Industrial  Alcohol 8vo,  4  oo 

Hind's  Inorganic  Chemistry 8vo,  3  oo 

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Holleman's  Text-book  of  Inorganic  Chemistry.     (Cooper.) 8vo,    2  50 

Text-book  of  Organic  Chemistry.     (Walker  and  Mott.) 8vof    2  50 

*  Laboratory  Manual  of  Organic  Chemistry.     (Walker.) I2mo,    i  oo 

4 


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Hopkins's  Oil-chemists'  Handbook 8vo,  3  oo 

Iddings's  Rock  Minerals 8vo,  5  oo 

Jackson's  Directions  for  Laboratory  Work  in  Physiological  Chemistry.  .8vo,  I  25 
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Keep's  Cast  Iron 8vo,  2  50 

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Lodge's  Notes  on  Assaying  and  Metallurgical  Laboratory  Experiments 8vo,  3  oo 

Low's  Technical  Method  of  Ore  Analysis 8vo,  3  oo 

Lunge's  Techno-chemical  Analysis.  (Cohn.) lamo  i  oo 

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Miller's  Manual  of  Assaying i2mo,  i  oo 

Cyanide  Process -. i2mo,  i  oo 

Minet's  Production  of  Aluminum  and  its  Industrial  Use.     (Waldo.) .  .  .  .  i2mo,  2  50 

Mixter's  Elementary  Text-book  of  Chemistry I2mo,  i  50 

Morgan's  An  Outline  of  the  Theory  of  Solutions  and  its  Results i2mo,  i  oo 

Elements  of  Physical  Chemistry I2mo,  3  oo 

*  Physical  Chemistry  for  Electrical  Engineers i2mo,  5  oo 

Morse's  Calculations  used  in  Cane-sugar  Factories i6mo,  morocco,  i  50 

*  MUT'S  History  of  Chemical  Theories  and  Laws 8vo,  4  oo 

Mulliken's  General  Method  for  the  Identification  of  Pure  Organic  Compounds. 

Vol.  I Large  8vo,  5  oo 

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Ostwald's  Conversations  on  Chemistry.     Part  One.     (Ramsey.) 12010,  150 

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*  Palmer's  Practical  Test  Book  of  Chemistry I2mo,  l  oo 

*  Pauli's  Physical  Chemistry  in  the  Service  of  Medicine.     (Fischer.) .  .  .  .  I2mo,  i  25 

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8vo,  paper,  50 

Pictet's  The  Alkaloids  and  their  Chemical  Constitution.     (Biddle.) 8vo,  5  oo 

Pinner's  Introduction  to  Organic  Chemistry.     (Austen.) i2mo,  i  50 

Poole's  Calorific  Power  of  Fuels 8vo,  3  oo 

Prescott  and  Winslow's  Elements  of  Water  Bacteriology,  with  Special  Refer- 
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*  Reisig's  Guide  to  Piece-dyeing 8vo,  25  oo 

Richards  and  Woodman's  Air,  Water,  and  Food  from  a  Sanitary  Standpoint.  .8vo ,  2  oo 

Ricketts  and  Miller's  Notes  on  Assaying 8vo,  3  oo 

Rideal's  Sewage  and  the  Bacterial  Purification  of  Sewage 8vo,  4  oo 

Disinfection  and  the  Preservation  of  Food 8vo,  4  oo 

Riggs's  Elementary  Manual  for  the  Chemical  Laboratory 8vo,  i  25 

Robine  and  Lenglen's  Cyanide  Industry.     (Le  Clerc.) 8vO»  4  do 

5 


Ruddiman's  Incompatibilities  in  Prescriptions 8vo,  2  oo 

*  Whys  in  Pharmacy '.  .  .  .  i2mo.  i  oo 

Sabin's  Industrial  and  Artistic  Technology  of  Paints  and  Varnish 8vo»  3  oo 

Salkowski's  Physiological  and  Pathological  Chemistry.     (Orndorff.) 8vo,  2  50 

Schimpf  s  Text-book  of  Volumetric  Analysis i2mo,  2  50 

Essentials  of  Volumetric  Analysis I2mo,  i  25 

*  Qualitative  Chemical  Analysis 8vo,  i   25 

Smith's  Lecture  Notes  on  Chemistry  for  Dental  Students 8vo,  2  50- 

Spencer's  Handbook  for  Chemists  of  Beet-sugar  Houses i6mo,  morocco  3  oo 

Handbook  for  Cane  Sugar  Manufacturers i6mo.  morocco.  3  oo 

Stockbridge's  Rocks  and  Soils 8vo,  2  50- 

*  Tillman's  Elementary  Lessons  in  Heat 8vo,  i  50- 

*  Descriptive  General  Chemistry 8vot  3  oc- 

Treadwell's  Qualitative  Analysis.     (Hall.) • 8vo,  3  oo 

Quantitative  Analysis.     (Hall.) 8vo,  4  oo 

Turneaure  and  Russell's  Public  Water-supplies 8vo,  5  oo 

Van  Deventer's  Physical  Chemistry  for  Beginners.     (Boltwood.) i2mo,  i  50 

*  Walke's  Lectures  on  Explosives 8vo.  4  oo 

Ware's  Beet-sugar  Manufacture  and  Refining.     Vol.  I Small  8vo,  4  oo 

Vol.  II Small  Svo,  5  co 

Washington's  Manual  of  the  Chemical  Analysis  of  Rocks 8vo,  2  oo 

Weaver's  Military  Explosives. 8vo,  3  oo- 

Wehrenfennig's  Analysis  and  Softening  of  Boiler  Feed -Water 8vo,  4  oo 

Wells's  Laboratory  Guide  in«Qualitative  Chemical  Analysis 8vo,  i  so- 
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Students I2mo,  i  50 

Text-book  of  Chemical  Arithmetic I2mo,  i  25 

Whipple's  Microscopy  of  Drinking-water 8vo,  3  50 

Wilson's  Cyanide  Processes i2mo,  i  50 

Chlorination  Process i2mo,  i  50 

Winton's  Microscopy  of  Vegetable  Foods 8vo,  7  50 

Wulling's    Elementary    Course    in  Inorganic,  Pharmaceutical,  and  Medical 

Chemistry 12010,  2  oa 


CIVIL  ENGINEERING. 

BRIDGES    AND   ROOFS.       HYDRAULICS.       MATERIALS   OF    ENGINEERING^ 
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Baker's  Engineers'  Surveying  Instruments i2mo,  3  oo 

Bixby's  Graphical  Computing  Table Paper  io£  X  24^  inches.  25. 

Breed  and  Hosmer's  Principles  and  Practice  of  Surveying 8vo,  3  oo 

*  Burr's  Ancient  and  Modern  Engineering  and  the  Isthmian  Canal 8vo,  3  50 

Comstock's  Field  Astronomy  for  Engineers 8vo,  2  50 

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Crandall's  Text-book  on  Geodesy  and  Least  Squares 8vo,  3  oo 

Davis's  Elevation  and  Stadia  Tables 8vo,  i  oa 

Elliott's  Engineering  for  Land  Drainage i2mo,  i  50 

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Folwell's  Sewerage.     (Designing  and  Maintenance.) 8vo,  3  oo 

Freitag's  Architectural  Engineering.     2d  Edition,  Rewritten 8vo,  3  50 

French  and  Ives's  Stereotomy 8vo,  2  50 

Goodhue's  Municipal  Improvements i2mo,  i  50 

Gore's  Elements  of  Geodesy 8vo,  2  50 

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Hayford's  Text-book  of  Geodetic  Astronomy 8vo,  3  oo 

6 


Bering's  Ready  Reference  Tables  (Conversion  Factors) i6mo,  morocco,  2  50 

"Howe's  Retaining  Walls  for  Earth I2mo,  i  25 

Hoyt  and  Grover's  River  Discharge 8vo,  2  oo 

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Ives  and  Hilts's  Problems  in  Surveying i6mo,  morocco,  i  50 

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Laplace's  Philosophical  Essay  on  Probabilities.    (Truscott  and  Emory.) .  i2mo,  2  oo 

Mahan's  Treatise  on  Civil  Engineering.     (1873.)     (Wood.) 8vo,  5  oo 

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Merriman  and  Brooks's  Handbook  for  Surveyors i6mo,  morocco,  2  oo 

N ugent's  Plane  Surveying 8vo,  3  50 

Ogden's  Sewer  Design i2mo,  2  oo 

Parsons's  Disposal  of  Municipal  Refuse. : 8vo,  2  oo 

Patton's  Treatise  on  Civil  Engineering 8vo  half  leather,  7  50 

Reed's  Topographical  Drawing  and  Sketching 4to,  5  oo 

Rideal's  Sewage  and  the  Bacterial  Purification  of  Sewage 8vo,  4  oo 

Riemer's  Shaft-sinking  under  Difficult  Conditions.     (Coming  and  Peele.) .  .8vo,  3  oo 

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Smith's  Manual  of  Topographical  Drawing.     (McMillan.) 8vo,  2  50 

Sondericker's  Graphic  Statics,  with  Applications  to  Trusses,  Beams,  and  Arches. 

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Taylor  and  Thompson's  Treatise  on  Concrete,  Plain  and  Reinforced 8vo,  5  oo 

Tracy's  Plane  Surveying I6mo,  morocco,  3  oo 

*  Trautwine's  Civil  Engineer's  Pocket-book i6mo,  morocco,  5  oo 

Venable's  Garbage  Crematories  in  America .8vo,  2  oo 

Wait's  Engineering  and  Architectural  Jurisprudence 8vo,  6  oo 

Sheep,  6  50 

Law  of  Operations  Preliminary  to  Construction  in  Engineering  and  Archi- 
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Sheep,  5  50 

Law  of  Contracts 8vo,  3  oo 

Warren's  Stereotomy — Problems  in  Stone-cutting 8vo,  2  50 

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Wilson's  Topographic  Surveying 8vo,  3  50 

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Design  and  Construction  of  Metallic  Bridges 8vo,  5  oo 

Du  Bois's  Mechanics  of  Engineering.     Vol.  II Small  4to,  10  oo 

Foster's  Treatise  on  Wooden  Trestle  Bridges 4to,  5  oo 

Fowler's  Ordinary  Foundations 8vo,  3  50 

Greene's  Roof  Trusses 8vo,  i  25 

Bridge  Trusses 8vo,  2  50 

Arches  in  Wood,  Iron,  and  Stone 8vo,  2  50 

Grimm's  Secondary  Stresses  in  Bridge  Trusses.     (In  Press.) 

Howe's  Treatise  on  Arches 8vo,  4  oo 

Design  of  Simple  Roof -trusses  in  Wood  and  Steel 8vo,  2  oo 

Symmetrical  Masonry  Arches 8vo,  2  50 

Johnson,  Bryan,  and  Turneaure's  Theory  and  Practice  in  the  Designing  of 

Modern  Framed  Structures Small  4to,  10  oo 

Merriman  and  Jacoby's  Text- book  on  Roofs  and  Bridges: 

Part  I.    Stresses  in  Simple  Trusses , 8vo,  2  50 

Part  II.    Graphic  Statics 8vo,  2  50 

Part  III.  Bridge  Design 8vo,  2  50 

Part  IV.  Higher  Structures 8vo,  2  50 

7 


Morison's  Memphis  Bridge.  , 4to,  10  o» 

Waddell's  De  Pontibus,  a  Pocket-book  for  Bridge  Engineers.  .  i6mo,  morocco,  2  oo 

*  Specifications  for  Steel  Bridges izmo,  50 

Wright's  Designing  of  Draw-spans.     Two  parts  in  one  volume 8vo,  3  50- 

HYDRAULICS. 

Barnes's  Ice  Formation 8vo,  3  oo> 

Bazin's  Experiments  upon  the  Contraction  of  the  Liquid  Vein  Issuing  from 

an  Orifice.     (Trautwine.) 8vo,  2  oo 

Bovey's  Treatise  on  Hydraulics 8vo,  5  oo- 

Church's  Mechanics  of  Engineering 8vo,  6  oo- 

Diagrams  of  Mean  Velocity  of  Water  in  Open  Channels paper,  i  so- 
Hydraulic  Motors 8vo,  2  oo- 

Coffin's  Graphical  Solution  of  Hydraulic  Problems i6mo,  morocco,  2  50 

Flather's  Dynamometers,  and  the  Measurement  of  Power i2mo,  3  oo 

Folwell's  Water-supply  Engineering 8vo,  4  oo- 

Frizell's  Water-power , 8vo,  5  oo- 

Fuertes's  Water  and  Public  Health i2mo,  i  50 

Water-filtration  Works i2mo.  2  50 

Ganguillet  and  Kutter's  General  Formula  for  the  Uniform  Flow  of  Water  in 

Rivers  and  Other  Channels.     (Bering  and  Trautwine.) 8vo,  4  oo 

Hazen's  Clean  Water  and  How  to  Get  It Large  I2mo,  l  5o 

Filtration  of  Public  Water-supply 8vo,  3  oo 

Hazlehurst's  Towers  and  Tanks  for  Water- works 8vo,  2  50- 

Herschel's  115  Experiments  on  the  Carrying  Capacity  of  Large,  Riveted,  Metal 

Conduits 8vo,  2  oo 

*  Hubbard  and  Kiersted's  Water- works  Management  and  Maintenance. .  .  8vo,  4  co- 
Mason's  Water-supply.     (Considered  Principally  from  a  Sanitary  Standpoint.) 

8vo,  4  oo- 

Merriman's  Treatise  on  Hydraulics 8vo,  5  oo 

*  Michie's  Elements  of  Analytical  Mechanics 8vo,  4  oo 

Schuyler's  Reservoirs   for   Irrigation,   Water-power,   and   Domestic   Water- 
supply Large  8vo,  5  oo 

*  Thomas  and  Watt's  Improvement  of  Rivers 4to,  6  oo- 

Turneaure  and  Russell's  Public  Water-supplies 8yo,  5  oo- 

Wegmann's  Design  and  Construction  of  Dams,     sth  Edition,  enlarged.  .  .4to,  6  oo- 

Water-supply  of  the  City  of  New  York  from  1658  to  1895 4to,  10  oo 

Whipple's  Value  of  Pure  Water Large  i2mo,  i  oo- 

Williams  and^Hazen's  Hydraulic  Tables • 8vo,  i  50* 

Wilson's  Irrigation  Engineering , ' Small  8vo,  4  oo- 

Wolff's  Windmill  as  a  Prime  Mover 8vo,  3  oo- 

Wood's  Turbines 8vo,  2  50- 

Elements  of  Analytical  Mechanics 8vo,  3  oo 


MATERIALS  OF  ENGINEERING. 

Baker's  Treatise  on  Masonry  Construction 8vo,  5  oo> 

Roads  and  Pavements 8vo,  5  oo> 

Black's  United  States  Public  Works Oblong  4to,  5  oo 

*  Bovey's  Strength  of  Materials  and  Theory  of  Structures 8vo,  7  50 

Burr's  Elasticity  and  Resistance  of  the  Materials  of  Engineering 8vo,  7  5<> 

Byrne's  Highway  Construction 8vo,  5  oo> 

Inspection  of  the  Materials  and  Workmanship  Employed  in  Construction. 

i6mo,  3  oo> 

Church's  Mechanics  of  Engineering 8vo,  6  oo> 

Du  Bois's  Mechanics  of  Engineering.     Vol.  I Small  410 .  7  5<> 

*Eckel's  Cements,  Limes,  and  Plasters 8vo,  6  oo 

8 


Jolinson's  Materials  of  Construction. Large  8vo,  6  oo 

Fowler's  Ordinary  Foundations 8vo,  3  50 

Graves's  Forest  Mensuration 8vo,  4  oo 

*  Greene's  Structural  Mechanics 8vo,  2  50 

Keep's  Cast  Iron 8vo,  2  50 

Lanza's  Applied  Mechanics .' 8vo,  7  50 

Martens's  Handbook  on  Testing  Materials.     (Henning.)     2  vols 8vo,  7  50 

Maurer's  Technical  Mechanics 8vo,  4  oo 

Merrill's  Stones  for  Building  and  Decoration 8vo,  5  oo 

Merriman's  Mechanics  of  Materials 8vo,  5  oo 

*  Strength  of  Materials i2mo,  i  oo 

Metcalf's  Steel.     A  Manual  for  Steel-users I2mo,  2  oo 

Patton's  Practical  Treatise  on  Foundations 8vo,  5  oo 

Richardson's  Modern  Asphalt  Pavements 8vo,  3  oo 

Richey's  Handbook  for  Superintendents  of  Construction i6mo,  mor.,  4  oo 

*  Ries's  Clays:  Their  Occurrence,  Properties,  and  Uses 8vo,  5  oo 

Rockwell's  Roads  and  Pavements  in  France I2mo,  i  25 

Sabin's  Industrial  and  Artistic  Technology  of  Paints  ar"i  Varnish 8vo,  3  oo 

*Schwarz's  Longleaf  Pine  in  Virgin  Forest i2mo,  i   25 

Smith's  Materials  of  Machines i2mo,  i  oo 

Snow's  Principal  Species  of  Wood 8vo,  3  50 

Spalding's  Hydraulic  Cement i2mo,  2  oo 

Text-book  on  Roads  and  Pavements i2mo,  2  oo 

Taylor  and  Thompson's  Treatise  on  Concrete,  Plain  and  Reinforced 8vo,  5  oo 

Thurston's  Materials  of  Engineering.     3  Parts 8vo,  8  oo 

Part  I.     Non-metallic  Materials  of  Engineering  and  Metallurgy 8vo,  2  oo 

Part  II.     Iron  and  Steel 8vo,  3  50 

Part  III.     A  Treatise  on  Brasses,  Bronzes,  and  Other  Alloys  and  their 

Constituents 8vo,  2  50 

Tillson's  Street  Pavements  and  Paving  Materials 8vo,  4  oo 

Turneaure  and  Maurer's  Principles  of  Reinforced  Concrete  Construction.   .8vo,  3  oo 

Waddell's  De  Pontibus.    (A  Pocket-book  for  Bridge  Engineers.).  .  i6mo,  mor.,  2  oo 

*  Specifications  for  Steel  Bridges i2mo,  50 

Wood's  (De  V.)  Treatise  on  the  Resistance  of  Materials,  and  an  Appendix  on 

the  Preservation  of  Timber 8vo,  2  oo 

Wood's  (De  V.)  Elements  of  Analytical  Mechanics 8vo,  3  oo 

Wood's  (M.  P.)  Rustless  Coatings:  Corrosion  and  Electrolysis  of  Iron  and 

Steel 8vo,  4  oo 


RAILWAY  ENGINEERING. 

Andrew's  Handbook  for  Street  Railway  Engineers 3x5  inches,  morocco,  I  25 

Berg's  Buildings  and  Structures  of  American  Railroads 4to,  5  oo 

Brook's  Handbook  of  Street  Railroad  Location i6mo,  morocco,  i  50 

Butt's  Civil  Engineer's  Field-book i6mo,  morocco,  2  50 

Crandall's  Transition  Curve i6mo,  morocco,  i  50 

Railway  and  Other  Earthwork  Tables 8vo,  i  50 

Crockett's  Methods  for  Earthwork  Computations.     (In  Press) 

Dawson's  "Engineering"  and  Electric  Traction  Pocket-book.  .  i6mo,  morocco  5  oo 

Dredge's  History  of  the  Pennsylvania  Railroad:    (1879) Paper,  5  oo 

Fisher's  Table  of  Cubic  Yards Cardboard,  25 

Godwin's  Railroad  Engineers'  Field-book  and  Explorers'  Guide.  .  .  i6mo,  mor.,  2  50 
•  Hudson's  Tables  for  Calculating  the  Cubic  Contents  of  Excavations  and  Em- 
bankments  8vo,  i  oo 

Molitor  and  Beard's  Manual  for  Resident  Engineers i6mo,  i  oo 

Nagle's  Field  Manual  for  Railroad  Engineers i6mo,  morocco,  3  oo 

Philbrick's  Field  Manual  for  Engineers i6mo,  morocco,  3  oo 

Raymond's  Elements  of  Railroad  Engineering.     (In  Press.) 

9 


Searles's  Field  Engineering x6mo,  morocco,  3  oo 

Railroad  Spiral i6mo,  morocco,  x  50 

Taylor's  Prismoidal  Formulae  and  Earthwork 8vo,  x  50 

*  Trautwine's  Method  of  Calculating  the  Cube  Contents  of  Excavations  and 

Embankments  by  the  Aid  of  Diagrams 8vo,  2  oo 

The  Field  Practice  of  Laying  Out  Circular  Curves  for  Railroads. 

i2mo,  morocco,  2  50 

Cross-section  Sheet Paper,  25 

Webb's  Railroad  Construction i6mo,  morocco,  5  oo 

Economics  of  Railroad  Construction Large  i2mo,  2  50 

Wellington's  Economic  Theory  of  the  Location  of  Railways Small  8vo,  5  oo 


DRAWING. 

Barr's  Kinematics  of  Machinery 8vo,  2  50 

*  Bartlett's  Mechanical  Drawing 8vo,  3  oo 

*  "                   "                   "       Abridged  Ed 8vo,  150 

Coolidge's  Manual  of  Drawing 8vo,  paper,  i  oo 

Coolidge  and  Freeman's  Elements  of  General  Drafting  for  Mechanical  Engi- 
neers  Oblong  4to,  2  50 

Durley's  Kinematics  of  Machines 8vo,  4  oo 

Emch's  Introduction  to  Projective  Geometry  and  its  Applications 8vo,  2  50 

Hill's  Text-book  on  Shades  and  Shadows,  and  Perspective 8vo,  2  oo 

Jamison's  Elements  of  Mechanical  Drawing 8vo,  2  50 

Advanced  Mechanical  Drawing 8vo,  2  oo 

Jones's  Machine  Design: 

Part  I.     Kinematics  of  Machinery 8vo,  i  50 

Part  II.     Form,  Strength,  and  Proportions  of  Parts 8vo,  3  oo 

MacCord's  Elements  of  Descriptive  Geometry 8vo,  3  oo 

Kinematics;  or,  Practical  Mechanism 8vo,  5  oo 

Mechanical  Drawing 4to,  4  oo 

Velocity  Diagrams 8vo,  i  50 

MacLeod's  Descriptive  Geometry Small  8vo,  i  50 

*  Mahan's  Descriptive  Geometry  and  Stone-cutting 8vo,  i  50 

Industrial  Drawing.  (Thompson.) 8vo,  3  50 

Mover's  Descriptive  Geometry 8vo,  2  oo 

Reed's  Topographical  Drawing  and  Sketching 4to,  5  oo 

Reid's  Course  in  Mechanical  Drawing 8vo,  2  oo 

Text-book  of  Mechanical  Drawing  and  Elementary  Machine  Design. 8vo,  3  oo 

Robinson's  Principles  of  Mechanism 8vo,  3  oo 

Schwamb  and  Merrill's  Elements  of  Mechanism 8vo,  3  oo 

Smith's  (R.  S.)  Manual  of  Topographical  Drawing.  (McMillan.) 8vo,  2  50 

Smith  (A.  W.)  and  Marx's  Machine  Design 8vo,  3  oo 


*  Titsworth's  Elements  of  Mechanical  Drawing Oblong  8vo, 

Warren's  Elements  of  Plane  and  Solid  Free-hand  Geometrical  Drawing.  i2mo, 

Drafting  Instruments  and  Operations i2mo, 

Manual  of  Elementary  Projection  Drawing i2mo, 

Manual  of  Elementary  Problems  in  the  Linear  Perspective  of  Form  and 

Shadow i2mo, 

Plane  Problems  in  Elementary  Geometry 12 mo, 


25 

00 

25 
50 

00 

25 

Elements  of  Descriptive  Geometry,  Shadows,  and  Perspective 8vo,  3  50 

General  Problems  of  Shades  and  Shadows 8vo,  3  oo 

Elements  of  Machine  Construction  and  Drawing 8vo,  7  50 

Problems,  Theorems,  and  Examples  in  Descriptive  Geometry 8vo,  2  50' 

Weisbach's    Kinematics    and    Power    of    Transmission.        (Hermann    and 

Klein.) 8vo,  5  oo 

Whelpley's  Practical  Instruction  in  the  Art  of  Letter  Engraving i2mo,  2  oo 

Wilson's  (H.  M.)  Topographic  Surveying 8vo,  3  50 

10 


Wilson's  (V.  T.)  Free-hand  Perspective 8vo,  2  50 

Wilson's  (V.  T.)  Free-hand  Lettering 8vo,  i  oo 

Woo  IPs  Elementary  Course  in  Descriptive  Geometry Large  8vo,  3  oo 

ELECTRICITY  AND  PHYSICS. 

*  Abegg's  Theory  of  Electrolytic  Dissociation.     (Von  Ende.) i2mo,  i   25 

Anthony  and  Bracken's  Text-book  of  Physics.     (Magie.) Small  8vo,  3  oo 

Anthony's  Lecture-notes  on  the  Theory  of  Electrical  Measurements.  .  .  .i2mo,  i  oo 

Benjamin's  History  of  Electricity 8vo,  3  oo 

Voltaic  Cell 8vo,  3  oo 

Betts's  Lead  Refining  and  Electrolysis.     (In  Press.) 

Classen's  Quantitative  Chemical  Analysis  by  Electrolysis.     (Boltwood.).8vo,  3  oo 

*  Collins's  Manual  of  Wireless  Telegraphy i2mo,  i  59 

Morocco,  2  oo 

Crehore  and  Squier's  Polarizing  Photo-chronograph 8vo,  3  oo 

*  Danneel's  Electrochemistry.     (Merriam.) i2mo,  i  25 

Dawson's  "Engineering"  and  Electric  Traction  Pocket-book.  i6mo,  morocco,  5  oo 
Dolezalek's  Theory  of  the  Lead  Accumulator  (Storage  Battery).    (Von  Ende.) 

i2mo,  2  50 

Duhem's  Thermodynamics  and  Chemistry.     (Burgess.) 8vo,  4  oo 

Flather's  Dynamometers,  and  the  Measurement  of  Power I2mo,  3  oo 

Gilbert's  De  Magnete.     (Mottelay.) 8vo,  2  50 

Hanchett's  Alternating  Currents  Explained i2mo,  i  oo 

Bering's  Ready  Reference  Tables  (Conversion  Factors) iomo,  morocco,  2  50 

Hobart  and  Ellis's  High-speed  Dynamo  Electric  Machinery.     (In  Press.) 

Holman's  Precision  of  Measurements 8vo,  2  oo 

Telescopic  Mirror-scale  Method,  Adjustments,  and   Tests.  .  .  .Large  8vo,  75 
Karapetoff's  Experimental  Electrical  Engineering.     (In  Press.) 

Kinzbrunner's  Testing  of  Continuous-current  Machines 8vo,  2  oo 

Landauer's  Spectrum  Analysis.     (Tingle.) 8vo,  3  oo 

Le  Chatelier's  High-temperature  Measurements.  (Boudouard — Burgess.)  i2mo,  3  oo 

Lob's  Electrochemistry  of  Organic  Compounds.     (Lorenz. ) 8vo,  3  oo 

*  Lyons'?  Treatise  on  Electromagnetic  Phenomena.   Vols.  I.  and  II.  8vo,  each,  6  oo 

*  Michie's  Elements  of  Wave  Motion  Relating  to  Sound  and  Light 8vo,  4  oo 

Niaudet's  Elementary  Treatise  on  Electric  Batteries.     (Fishback.) i2mo,  2  50 

Norris's  Introduction  to  the  Study  of  Electrical  Engineering.     (In  Press.) 

*  Parshall  and  Hobart's  Electric  Machine  Design 410,  half  morocco,  12  50 

Reagan's  Locomotives:    Simple,  Compound,  and  Electric.      New  Edition. 

Large  12 mo,  3  50 

*  Rosenberg's  Electrical  Engineering.     (Haldane  Gee — Kinzbrunner.).  .  .8vo,  oo 

Ryan,  Norris,  and  Hoxie's  Electrical  Machinery.     Vol.  I 8vo,  50 

Thurston's  Stationary  Steam-engines 8vo,  50 

*  Tillman's  Elementary  Lessons  in  Heat 8vo,  50 

Tory  and  Pitcher's  Manual  of  Laboratory  Physics Small  8vo,  oo 

Ulke's  Modern  Electrolytic  Copper  Refining 8vo,  3  oo 

LAW. 

*  Davis's  Elements  of  Law 8vo,  2  50 

*  Treatise  on  the  Military  Lav/  of  United  States 8vo,  7  oo 

*  Sheep,  7  SO 

*  Dudley's  Military  Law  and  the  Procedure  oi  Courts-martial  ...    Large  i2mo,  2  50 

Manual  for  Courts-martial i6mo,  morocco,  i  50 

Wait's  Engineering  and  Architectural  Jurisprudence 8vo,  6  oo 

Sheep,  6  50 

Law  of  Operations  Preliminary  to  Construction  in  Engineering  and  Archi- 
tecture  8vo  5  oo 

Sheep,  5  50 

Law  of  Contracts 8vo,  3  oo 

Winthrop's  Abridgment  of  Military  Law i2mo,  2  50 

11 


MANUFACTURES. 

Bernadou's  Smokeless  Powder — Nitro-cellulose  and  Theory  of  the  Cellulose 

Molecule i2mo,  2  50 

Holland's  Iron  Founder lamo,  2  50 

The  Iron  Founder,"  Supplement 1 2mo,  2  50 

Encyclopedia  of  Founding  and  Dictionary  of  Foundry  Terms  Used  in  the 

Practice  of  Moulding i2mo,  3  oa 

*  Claassen's  Beet-sugar  Manufacture.    (Hall  and  Rolfe.) 8vo,  3  oa 

*  Eckel's  Cements,  Limes,  and  Plasters 8vo,  6  oo 

Eissler's  Modern  High  Explosives 8vo,  4  oa 

Eff rant's  Enzymes  and  their  Applications.     (Prescott.) 8vot  3  oa 

Fitzgerald's  Boston  Machinist i2mo,  i  oo 

Ford's  Boiler  Making  for  Boiler  Makers i8mo'.  i  oo 

Herrick's  Denatured  or  Industrial  Alcohol 8vo,  4  oo 

HoUey  and  Ladd's  Analysis  of  Mixed  Paints,  Color  Pigments,  and  Varnishes. 

(In  Press.) 

Hopkins 's  Oil-chemists'  Handbook 8vo,  3  oo 

Keep's  Cast  Iron 8vo5  2  50 

Leach's  The  Inspection  and  Analysis  of  Food  with  Special  Reference  to  State 

Control Large  8vo,  7  50 

*  McKay  and  Larsen's  Principles  and  Practice  of  Butter-making 8vo,  i  50 

Maire's  Modern  Pigments  and  their  Vehicles.     (In  Press.) 

Matthews's  The  Textile  Fibres.     2d  Edition,  Rewritten 8vo,  4  oa 

Metcalf's  Steel.     A  Maunal  for  Steel-users i2mo,  2  oa 

Metcalf e's  Cost  of  Manufactures — And  the  Administration  of  Workshops    .  8vo,  5  oo 

Meyer's  Modern  Locomotive  Construction 4to,  10  oa 

Morse's  Calculations  used  in  Cane-sugar  Factories i6mo,  morocco,  i   50 

*  Reisig's  Guide  to  Piece-dyeing 8vo,  25  oa 

Rice's  Concrete-block  Manufacture 8vo,  2  oa 

Sabin's  Industrial  and  Artistic  Technology  of  Paints  and  Varnish 8vo,  3  oo 

Smith's  Press-working  of  Metals 8vo,  3  oo 

Spalding's  Hydraulic  Cement i2mo,  2  oo 

Spencer's  Handbook  for  Chemists  of  Beet-sugar  Houses i6mo,  morocco,  3  oa 

Handbook  for  Cane  Sugar  Manufacturers i6mo,  morocco,  3  oa 

Taylor  and  Thompson's  Treatise  on  Concrete,  Plain  and  Reinforced 8vo,  5  oa 

Thurston's  Manual  of  Steam-boilers,  their  Designs,  Construction  and  Opera- 
tion   8vo,  5  oa 

Ware's  Beet-sugar  Manufacture  and  Refining.     Vol.  I Small  8vo,  4  oo 

Vol.11 8vo.  5  oo 

Weaver's  Military  Explosives 8vo,  3  oo 

West's  American  Foundry  Practice i2mo,  2  50 

Moulder's  Text-book i2mo,  2  50 

Wolff's  Windmill  as  a  Prime  Mover 8vo,  3  oa 

Wood's  Rustless  Coatings:  Corrosion  and  Electrolysis  of  Iron  and  Steel .  .8vo,  4  oa 

MATHEMATICS. 

Baker's  Elliptic  Functions 8vo,  i  50 

Briggs's  Elements  of  Plane  Analytic  Geometry 12 mo,  i  oa 

Buchanan's  Plane  and  Spherical  Trigonometry.     (In  Press.) 

Compton's  Manual  of  Logarithmic  Computations lamo,  i   Sa 

Davis's  Introduction  to  the  Logic  of  Algebra 8vo,  i  50 

*  Dickson's  College  Algebra .  .  .Large  i2mo,  i  50 

*  Introduction  to  the  Theory  of  Algebraic  Equations Large  i2mo,  i   25 

Emch's  Introduction  to  Projective  Geometry  and  its  Applications 8vo,  2  50 

Halsted's  Elements  of  Geometry 8vo,  i  75 

Elementary  Synthetic  Geometry 8vo,  i  50 

*  Rational  Geometry  . I2mo,  I  SO 

12 


*  Johnson's  (J.  B.)  Three-place  Logarithmic  Tables:  Vest-pocket  size. paper,         15 

100  copies  for     5  oo 

*  Mounted  on  heavy  cardboard,  8  X 10  inches,          25 

10  copies  for     2  oo 
Johnson's  (W.  W.)  Elementary  Treatise  on  Differential  Calculus.  .Small  8vo,     3  oo 

Elementary  Treatise  on  the  Integral  Calculus Small  8vo,     i  50 

Johnson's  (W.  W.)  Curve  Tracing  in  Cartesian  Co-ordinates i2mo,     i  oo 

Johnson's  (W.  W.)  Treatise  on  Ordinary  and  Partial  Differential  Equations. 

Small  8vo,     3  50 

Johnson's  Treatise  on  the  Integral  Calculus Small  8vo,     3  oo 

Johnson's  (W.  W.)  Theory  of  Errors  and  the  Method  of  Least  Squares.  i2mo,     i   50 

*  Johnson's  (W.  W.)  Theoretical  Mechanics i2mo,     3  oo 

Laplace's  Philosophical  Essay  on  Probabilities.     (Truscott  and  Emory. ).i2mo,     2  oo 

*  Ludlow  and  Bass.     Elements  of  Trigonometry  and  Logarithmic  and  Other 

Tables 8vo,     3  oo 

Trigonometry  and  Tables  published  separately Each,     2  oo 

*  Ludlow's  Logarithmic  and  Trigonometric  Tables 8vo,     i  oo 

Manning's  IrrationalN umbers  and  their  Representation  bySequences  and  Series 

i2mo,     i   25 
Mathematical  Monographs.     Edited  by  Mansfield  Merriman  and  Robert 

S.  Woodward Octavo,  each     i  oo 

No.  i.  History  of  Modern  Mathematics,  by  David  Eugene  Smith. 
No.  2.  Synthetic  Projective  Geometry,  by  George  Bruce  Halsted. 
Kb.  3.  Determinants,  by  Laenas  Gifford  Weld.  No.  4.  Hyper- 
bolic Functions,  by  James  McMahon.  No.  $.  Harmonic  Func- 
tions, by  William  E.  Byerly.  No.  6.  Grassmann's  Space  Analysis, 
by  Edward  W.  Hyde.  No.  7.  Probability  and  Theory  of  Errors, 
by  Robert  S.  Woodward.  No.  8.  Vector  Analysis  and  Quaternions, 
by  Alexander  Macfarlane.  No.  9.  Differential  Equations,  by 
William  Woolsey  Johnson.  No.  10.  The  Solution  of  Equations, 
by  Mansfield  Merriman.  No.  n.  Functions  of  a  Complex  Variable, 
by  Thomas  S.  Fiskc. 

Maurer's  Technical  Mechanics 8vo,    4  oo 

Merriman's  Method  of  Least  Squares 8vo,    2  oo 

Rice  and  Johnson's  Elementary  Treatise  on  the  Differential  Calculus. .  Sm.  8vo,    3  oo 
Differential  and  Integral  Calculus.     2  vols.  in  one Small  8vo,    2  50 

*  Veblen  and  Lennes's  Introduction  to  the  Real  Infinitesimal  Analysis  of  One 

Variable 8vo,    2  oo 

Wood's  Elements  of  Co-ordinate  Geometry 8vo,     2  oo 

Trigonometry:   Analytical,  Plane,  and  Spherical 12 mo,     i  oo 


MECHANICAL  ENGINEERING. 

MATERIALS  OF  ENGINEERING,  STEAM-ENGINES  AND  BOILERS. 

Bacon's  Forge  Practice i2mo,  i  50 

Baldwin's  Steam  Heating  for  Buildings i2mo,  2  50 

Barr's  Kinematics  of  Machinery 8vo,  2  50 

*  Bartlett's  Mechanical  Drawing 8vo,  3  oo 

*  "  "  "         Abridged  Ed 8vo,  i  50 

Benjamin's  Wrinkles  and  Recipes i2mo,  2  oo 

Carpenter's  Experimental  Engineering 8vo,  6  oo 

Heating  and  Ventilating  Buildings 8vo,  4  oo 

Clerk's  Gas  and  Oil  Engine Small  8vo,  4  oo 

Coolidge's  Manual  of  Drawing '. 8vo,  paper,  i  oo 

Coolidge  and  Freeman's  Elements  of  General  Drafting  for  Mechanical  En- 
gineers  Oblong  4to,  2  50 

Cromwell's  Treatise  on  Toothed  Gearing i2mo,  i  50 

Treatise  on  Belts  and  Pulleys.  .  •. i2mo,  i  50 

13 


Durley's  Kinematics  of  Machines 8vo,  4  oo 

Flather's  Dynamometers  and  the  Measurement  of  Power i2mo,  3  oo 

Rope  Driving i2mo,  2  oo 

Gill's  Gas  and  Fuel  Analysis  for  Engineers , i2mo,  i  25 

Hall's  Car  Lubrication i2mo,  i  oo 

Bering's  Ready  Reference  Tables  (Conversion  Factors) i6mo,  morocco,  2  50 

Button's  The  Gas  Engine 8vo,  5  oo 

Jamison's  Mechanical  Drawing 8vo,  2  50 

Jones's  Machine  Design: 

Part  I.     Kinematics  of  Machinery ' 8vo,  i  50 

Part  II.     Form,  Strength,  and  Proportions  of  Parts 8vo,  3  oo 

Kent's  Mechanical  Engineers'  Pocket-book i6mo,  morocco,  5  oo 

Kerr's  Power  and  Power  Transmission 8vo,  2  oo 

Leonard's  Machine  Shop,  Tools,  and  Methods 8vo,  4  oo 

*  Lorenz's  Modern  Refrigerating  Machinery.    (Pope,  Haven,  and  Dean.) .  .  8vo,  4  oo 
MacCord's  Kinematics;  or,  Practical  Mechanism 8vo,  5  oo 

Mechanical  Drawing 4to,  4  oo 

Velocity  Diagrams 8vo ,  i  50 

MacFarland's  Standard  Reduction  Factors  for  Gases 8vo,  i  50 

Mahan's  Industrial  Drawing.     (Thompson.) | 8vo,  3  50 

Poole's  Calorific  Power  of  Fuels 8vo,  3  oo 

Reid's  Course  in  Mechanical  Drawing 8vo,  2  oo 

Text-book  of  Mechanical  Drawing  and  Elementary  Machine  Design. 8 vo,  3  oo 

Richard's  Compressed  Air i2mo,  i  50 

Robinson's  Principles  of  Mechanism 8vo,  3  oo 

Schwamb  and  Merrill's  Elements  of  Mechanism 8vo,  3  oo 

Smith's  (O.)  Press- working  of  Metals 8vo,  3  oo 

Smith  (A.  W.)  and  Marx's  Machine  Design 8vo,  3  oo 

Thurston's   Treatise    on   Friction  and   Lost   Work   in   Machinery   and   Mill 

Work 8vo,  3  oo 

Animal  as  a  Machine  and  Prime  Motor,  and  the  Laws  of  Energetics .  i2mo,  i  oo 

Tillson's  Complete  Automobile  Instructor i6mo,  i  50 

Morocco,  2  oo 

Warren's  Elements  of  Machine  Construction  and  Drawing 8vo,  7  50 

Weisbach's    Kinematics    and    the    Power    of    Transmission.     (Herrmann — 

Klein.) 8vo,  5  oo 

Machinery  of  Transmission  and  Governors.     (Herrmann — Klein.).  .8vo,  5  oo 

Wolff's  Windmill  as  a  Prime  Mover 8vo,  3  oo 

Wood's  Turbines 8vo,  2  50 

MATERIALS   OF   ENGINEERING. 

*  Bovey's  Strength  of  Materials  and  Theory  of  Structures 8vo,  7  50 

Burr's  Elasticity  and  Resistance  of  the  Materials  of  Engineering.     6th  Edition. 

Reset 8vo,  7  50 

Church's  Mechanics  of  Engineering 8vo,  6  oo 

*  Greene's  Structural  Mechanics 8vo,  2  50 

Johnson's  Materials  of  Construction 8vo,  6  oo 

Keep's  Cast  Iron 8vo,  2  50 

Lanza's  Applied  Mechanics 8vo,  7  50 

Martens 's  Handbook  on  Testing  Materials.     (Henning.) 8vo,  7  50 

Maurer's  Technical  Mechanics 8vo,  4  oo 

Merriman's  Mechanics  of  Materials 8vo,  5  oo 

*  Strength  of  Materials i2mo,  i  oo 

Metcalf's  Steel.     A  Manual  for  Steel-users i2mo,  2  oo 

Sabin's  Industrial  and  Artistic  Technology  of  Paints  and  Varnish 8vo,  3  oo 

Smith's  Materials  of  Machines : i2mo,  i  oo 

Thurston's  Materials  of  Engineering 3  vols.,  8vo,  8  oo 

Part  II.     Iron  and  Steel 8vo,  3  50 

Part  IH.     A  Treatise  on  Brasses,  Bronzes,  and  Other  Alloys  and  their 

Constituents. 8vo,  2  50 

14 


Wood's  (De  V.)  Treatise  on  the  Resistance  of  Materials  and  an  Appendix  on 

the  Preservation  of  Timber 8vo,  2  oo 

Elements  of  Analytical  Mechanics 8vo,  3  oo 

Wood's  (M.  P.)  Rustless  Coatings:    Corrosion  and  Electrolysis  of  Iron  and 

Steel 8vo,  4  oo 

STEAM-ENGINES  AND  BOILERS. 

Berry's  Temperature-entropy  Diagram i2mo,  i  25 

Carnot's  Reflections  on  the  Motive  Power  of  Heat.     (Thurston.)s, i2mo,  i  50 

Creighton's  Steam-engine  and  other  Heat-motors         8vo,  500 

Dawson's  "Engineering"  and  Electric  Traction  Pocket-book.  .  .  .i6mo,  mor.,  5  oo 

Ford's  Boiler  Making  for  Boiler  Makers i8mo,  i  oo 

Goss's  Locomotive  Sparks 8vo,  2  oo 

Locomotive  Performance 8vo,  5  oo 

Hemenway's  Indicator  Practice  and  Steam-engine  Economy i2mo,  2  oo 

Button's  Mechanical  Engineering  of  Power  Plants 8vo,  5  oo 

Heat  and  Heat-engines 8vo,  5  oo 

Kent's  Steam  boiler  Economy 8vo,  4  oo 

Kneass's  Practice  and  Theory  of  the  Injector 8vo,  i   50 

MacCord's  Slide-valves 8vo,  2  oo 

Meyer's  Modern  Locomotive  Construction 4to,  10  oc 

Peabody's  Manual  of  the  Steam-engine  Indicator i2mo,  t  50 

Tables  of  the  Properties  of  Saturated  Steam  and  Other  Vapors 8vo,  i  oo 

Thermodynamics  of  the  Steam-engine  and  Other  Heat-engines 8vo,  5  oo 

Valve-gears  for  Steam-engines 8vo,  2  50 

Peabody  and  Miller's  Steam-boilers 8vo,  4  oo 

Pray's  Twenty  Years  with  the  Indicator Large  8vo,  2  50 

Pupin's  Thermodynamics  of  Reversible  Cycles  in  Gases  and  Saturated  Vapors. 

(Osterberg.) i2mo,  i  25 

Reagan's  Locomotives:   Simple,  Compound,  and  Electric.     New  Edition. 

Large  12 mo,  3  50 

Sinclair's  Locomotive  Engine  Running  and  Management 12 mo,  2  oo 

Smart's  Handbook  of  Engineering  Laboratory  Practice 121110,  2  50 

Snow's  Steam-boiler  Practice 8vo,  3  oo 

Spangler's  Valve-gears. 8vo,  2  50 

Notes  on  Thermodynamics i2mo,  i  oo 

Spangler,  Greene,  and  Marshall's  Elements  of  Steam-engineering 8vo,  3  oo 

Thomas's  Steam-turbines 8vo,  3  50 

Thurston's  Handy  Tables 8vo,  i  50 

Manual  of  the  Steam-engine 2  vols.,  8vo,  10  oo 

Part  I.     History,  Structure,  and  Theory. 8vo,  6  oo 

Part  II.     Design,  Construction,  and  Operation 8vo,  6  oo 

Handbook  of  Engine  and  Boiler  Trials,  and  the  Use  of  the  Indicator  and 

the  Prony  Brake 8vo,  5  oo 

Stationary  Steam-engines 8vo,  2  50 

Steam-boiler  Explosions  in  Theory  and  in  Practice i2mo,  i  50 

Manual  of  Steam-boilers,  their  Designs,  Construction,  and  Operation  8vo,  5  oo 

Wehrenfenning's  Analysis  and  Softening  of  Boiler  Feed-water  (Patterson)  8vo,  4  oo 

Weisbach's  Heat,  Steam,  and  Steam-engines.     (Du  Bois.) 8vo,  5  oo 

Whitham's  Steam-engine  Design 8vo,  5  oo 

Wood's  Thermodynamics,  Heat  Motors,  and  Refrigerating  Machines. .  .8vo,  4  oo 


MECHANICS  AND  MACHINERY. 

Barr's  Kinematics  of  Machinery 8vo,  2  50 

*  Bovey's  Strength  of  Materials  and  Theory  of  Structures   8vo,  7  50 

Chase's  The  Art  of  Pattern-making I2mo,  2  50 

15 


Church's  Mechanics  of  Engineering 8vo,  6  oo 

Notes  and  Examples  in  Mechanics 8vo,  2  oo 

Compton's  First  Lessons  in  Metal-working i2mo,  i  50 

Compton  and  De  Groodt's  The  Speed  Lathe i2mo,  i   «;o 

Cromwell's  Treatise  on  Toothed  Gearing i2mo,  i  50 

Treatise  on  Belts  and  Pulleys i2mo,  i  50 

Dana's  Text-book  of  Elementary  Mechanics  for  Colleges  and  Schools.  .i2mo,  i  50 

Dingey's  Machinery  Pattern  Making I2mo,  2  oo 

Dredge's  Record  of  the  Transportation  Exhibits  Building  of  the  World's 

Columbian  Exposition  of  1893 4to  half  morocco,  5  oo 

Du  Bois's  Elementary  Principles  of  Mechanics : 

Vol.      I.     Kinematics 8vo,  3  50 

Vol.    II.     Statics 8vo,  4  oo 

Mechanics  of  Engineering.     Vol.    I Small  4to,  7  50 

Vol.  II Small  4to,  10  oo 

Durley's  Kinematics  of  Machines 8vo,  4  oo 

Fitzgerald's  Boston  Machinist i6mo,  i  oo 

Flather's  Dynamometers,  and  the  Measurement  of  Power i2mo,  3  oo 

Rope  Driving i2mo,  2  oo 

Goss's  Locomotive  Sparks 8vo,  2  oo 

Locomotive  Performance 8vo,  5  oo 

*  Greene's  Structural  Mechanics 8vo,  2  50 

Hall's  Car  Lubrication lamo,  i  oo 

Hobart  and  Ellis's  High-speed  Dynamo  Electric  Machinery.     (In  Press.) 

Holly's  Art  of  Saw  Filing i8mo,  75 

James's  Kinematics  of  a  Point  and  the  Rational  Mechanics  of  a  Particle. 

Small  8vo,  2  oo 

*  Johnson's  (W.  W.)  Theoretical  Mechanics i2mo,  3  oo 

Johnson's  (L.  J.)  Statics  by  Graphic  and  Algebraic  Methods 8vo,  2  oo 

Jones's  Machine  Design: 

Part    I.     Kinematics  of  Machinery 8vo,  i  50 

Part  II.     Form,  Strength,  and  Proportions  of  Parts.  ... 8vo,  3  oo 

Kerr's  Power  and  Power  Transmission 8vo,  2  oo 

Lanza's  Applied  Mechanics 8vo,  7  50 

Leonard's  Machine  Shop,  Tools,  and  Methods 8vo,  4  oo 

*  Lorenz's  Modern  Refrigerating  Machinery.     (Pope,  Haven,  and  Dean.). 8vo,  4  oo 
MacCord's  Kinematics;  or,  Practical  Mechanism 8vo,  5  oo 

Velocity  Diagrams 8vo,  i  50 

*  Martin's  Text  Book  on  Mechanics,  Vol.  I,  Statics i2mo,  i   25 

Vol.  2,  Kinematics  and  Kinetics  .  .I2mo,  1  50 

Maurer's  Technical  Mechanics 8vo,  4  oo 

Merriman's  Mechanics  of  Materials 8vo,  5  oo 

*  Elements  of  Mechanics i2mo,  i  oo 

*  Michie's  Elements  of  Analytical  Mechanics 8vo,  4  oo 

*  Parshall  and  Hobart's  Electric  Machine  Design 4 to,  half  morocco,  12  50 

Reagan's  Locomotives :  Simple,,  Compound,  and  Electric.     New  Edition. 

Large  i2mo,  3  5o 

Reid's  Course  in  Mechanical  Drawing 8vo,  2  oo 

Text-book  of  Mechanical  Drawing  and  Elementary  Machine  Design. 8vo,  3  oo 

Richards's  Compressed  Air i2mo,  i  50 

Robinson's  Principles  of  Mechanism 8vo,  3  oo 

Ryan,  Norris,  and  Hoxie's  Electrical  Machinery.  Vol.  1 8vo,  2  50 

Sanborn's  Mechanics:  Problems Large  i2mo,  i  50 

Schwamb  and  Merrill's  Elements  of  Mechanism 8vo,  3  oo 

Sinclair's  Locomotive-engine  Running  and  Management 12 mo,  2  oo 

Smith's  (O.)  Press-working  of  Metals 8vo,  3  oo 

Smith's  (A.  W.)  Materials  of  Machines i2mo,  i  oo 

Smith  (A.  W.)  and  Marx's  Machine  Design 8vo,  3  oo 

Sorel' s  Carbureting  and  Combustion  of  Alcohol  Engines.  (Woodward  and 

Preston.) Large  8vo,  3  o» 

16 


Spangler,  Greene,  and  Marshall's  Elements  of  Steam-engineering 8vo,  3  oo 

Thurston's  Treatise  on  Friction  and  Lost  Work  in    Machinery  and    Mill 

Work 8vo,  3  oo 

Animal  as  a  Machine  and  Prime  Motor,  and  the  Laws  of  Energetics.  I2mo,  i  oo 

Tillson's  Complete  Automobile  Instructor , i6mo,  i  50 

Morocco,  2  oo 

Warren's  Elements  of  Machine  Construction  and  Drawing 8vo,  7  50 

Weisbach's  Kinematics  and  Power  of  Transmission.   (Herrmann — Klein.). 8vo.  5  oo 

Machinery  of  Transmission  and  Governors.      (Herrmann — Klein.). 8vo.  5  oo 

Wood's  Elements  of  Analytical  Mechanics 8vo,  3  oo 

Principles  of  Elementary  Mechanics I2mo,  i  25 

Turbines. 8vo,  2  50 

The  World's  Columbian  Exposition  of  1893 4to,  I  oo 

MEDICAL. 

*  Bolduan's  Immune  Sera izmo,  1  50 

De  Fursac's  Manual  of  Psychiatry.     (Rosanoff  and  Collins.).    .  .  .Large  i2mo,  2  50 

Ehrlich's  Collected  Studies  on  Immunity.     (Bolduan.) 8vo,  6  oo 

*  Fischer's  Physiology  of  Alimentation .Large  12mo,  cloth,  2  oo 

Hammarsten's  Text-book  on  Physiological  Chemistry.     (Mandel.) 8vo,  4  oo 

Lassar-Cohn's  Practical  Urinary  Analysis.     (Lorenz.) 1211:0,  oo 

*  Pauli's  Physical  Chemistry  m  the  Service  of  Medicine.     (Fischer.) .  .  .  .  12010,  25 

*  Pozzi-Escot's  The  Toxins  and  Venoms  and  their  Antibodies.     (Cohn.).  i2mo,  oo 

Rostoski's  Serum  Diagnosis.     (Bolduan.) i2mo,  oo 

Salkowski's  Physiological  and  Pathological  Chemistry.     (Orndorff.) 8vo,  50 

*  Satterlee's  Outlines  of  Human  Embryology i2mo,  25 

Steel's  Treatise  on  the  Diseases  of  the  Dog 8vo,  50 

Von  Behring's  Suppression  of  Tuberculosis.     (Bolduan.) i2mo,  oo 

Woodhull's  Notes  on  Military  Hygiene i6mo,  50 

*  Personal  Hygiene i2mo,  oo 

Wulling's  An  Elementary  Course  in  Inorganic  Pharmaceutical  and  Medical 

Chemistry i2mo,  2  oo 

METALLURGY. 

Betts's  Lead  Refining  by  Electrolysis.    (In  Press.) 

Egleston's  Metallurgy  of  Silver,  Gold,  and  Mercury: 

Vol.    I.     Silver 8vo,  7  50 

Vol.  II.     Gold  and  Mercury 8vo,  7  50 

Goesel's  Minerals  and  Metals:     A  Reference  Book , .  . . .  i6mo,  mor.  3  oo 

*  Iles's  Lead-smelting i2mo, 

Keep's  CastJron 8vo, 

Kunhardt's  Practice  of  Ore  Dressing  in  Europe 8vo, 

Le  Chatelier's  High-temperature  Measurements.  (Boudouard — Burgess.  )i2mo, 

Metcalf's  Steel.     A  Manual  for  Steel-users.  .  , i2mo, 

Miller's  Cyanide  Process i2mo, 

Minet's  Production  of  Aluminum  and  its  Industrial  Use.     (Waldo.). , .  .  i2mo, 

Robine  and  Lenglen's  Cyanide  Industry.     (Le  Clerc.) 8vo, 

Smith's  Materials  of  Machines.    . 


.  i2mo, 


Thurston's  Materials  of  Engineering.     In  Three  Parts 8vo,  8  ©o 

Part    II.     Iron  and  Steel 8vo,  3  50 

Part  III.     A  Treatise  on  Brasses,  Bronzes,  and  Other  Alloys  and  their 

Constituents 8vOf  2  5O 

Ulke's  Modern  Electrolytic  Copper  Refining 8vo,  3  oo 

MINERALOGY. 

Barringer's  Description  of  Minerals  of  Commercial  Value.    Oblong,  morocco,  2  50 

Boyd's  Resources  of  Southwest  Virginia gvo,  3  oo 

17 


Boyd's  Map  of  Southwest  Virignia Pocket-book  form,  a  oi> 

*  Browning's  Introduction  to  the  Rarer  Elements 8vo,  150 

Brush's  Manual  of  Determinative  Mineralogy.     (Penfield.) 8vo,  4  oo 

Chester's  Catalogue  of  Minerals. . . 8vo,  paper,  I  oo 

Cloth,  i  25 

Dictionary  of  the  Names  of  Minerals 8vo,  3  50 

Dana's  System  of  Mineralogy Large  8vo,  half  leather,  12  50 

First  Appendix  to  Dana's  New  "  System  of  Mineralogy." Large  8vo,  i  oo 

Text-book  of  Mineralogy 8vo,  4  oo 

Minerals  and  How  to  Study  Them I2mo,  i  50 

Catalogue  of  American  Localities  of  Minerals Large  8vo,  i  oo 

Manual  of  Mineralogy  and  Petrography i2mo  2  oo 

Douglas's  Untechnical  Addresses  on  Technical  Subjects xarno,  i  oo 

Eakle's  Mineral  Tables 8vo,  i  25 

Egleston's  Catalogue  of  Minerals  and  Synonyms 8vo,  2  50 

Goesel's  Minerals  and  Metals :     A  Reference  Book ibmo,  mor.  3  oo 

Groth's  Introduction  to  Chemical  Crystallography  (Marshall) i2mo,  i  25 

Iddings's  Rock  Minerals 8vo,  5  oo 

Johannsen's  Key  for  the  Determination  of  Rock-forming  Minerals   in   Thin 
Sections .     ( In  P  ress. ) 

*  Martin's  Laboratory  Guide  to  Qualitative  Analysis  with  the  Blowpipe.  I2mo,        60 
Merrill's  Non-metallic  Minerals .  Their  Occurrence  and  Uses 8vo ,  4  oo 

Stones  for  Building  and  Decoration 8vo,    500 

*  Penfield's  Notes  on  Determinative  Mineralogy  and  Record  of  Mineral  Tests. 

8vo,  paper,  50 

Tables  of  Minerals 8vo,  1  00 

*  Richards's  Synopsis  of  Mineral  Characters 12010.  morocco,  i  25 

*  Ries's  Clays.  Their  Occurrence.  Properties,  and  Uses 8vo,  5  oo 

Rosenbusch's   Microscopical   Physiography   of   the   Rock-making  Minerals. 

(Iddings.) 8vo,  5  oo 

*  Tillman's  Text-book  of  Important  Minerals  and  Rocks 8vo,  2  oo 

MINING. 

Beard's  Mine  Gases  and  Explosions.     (In  Press.) 

Boyd's  Resources  of  Southwest  Virginia 8vo,  3  oo 

Map  of  Southwest  Virginia Pocket-book  form,  2  oo 

Douglas's  Untechnical  Addresses  on  Technical  Subjects i2mo,  I  oo 

Eissler's  Modern  High  Explosives 8vo,  4  oo 

Goesel's  Minerals  and  Metals;     A  Reference  Book.  .      i6mo,  mor.  3  oo 

Goodyear's  Coal-mines  of  the  Western  Coa-,t  of  the  United  States i2mo,  2  50 

Ihlseng's  Manual  of  Mining.   v  .8vo,  5  oo 

*  Iles's  Lead-smelting i2mo,  2  50 

Kunhardt's  Practice  of  Ore  Dressing  in  Europe 8vo,  i  50 

Miller's  Cyanide  Process i2mo,  i  oo 

O'Driscoll's  Notes  on  the  Treatment  of  Gold  Ores 8vo,  2  oo 

Robine  and  Lenglen's  Cyanide  Industry.     (Le  Clerc.) 8vo,  4  oo 

Weaver's  Military  Explosives 8vo,  3  oo 

Wilson's  Cyanide  Processes i2mo,  i  50 

Chlorination  Process.  .    limo,  i  50 

Hydraulic  and  Placer  Mining.     2d  edition,  rewritten i2mo,  2  50 

Treatise  on  Practical  and  Theoretical  Mine  Ventilation i2mo,  i  25 

SANITARY  SCIENCE. 

Basnore's  Sanitation  of  a  Country  House. 12010,  i  oo 

*  Outlines  of  Practical  Sanitation , i2mo,  i  25 

Folwell's  Sewerage.     (Designing,  Construction,  and  Maintenance.) 8vo,  3  60 

Water-supply  Engineering 8vo,  4  oo 

18 


Fowler's  Sewage  Works  Analyses 12010,  2  oo 

Fuertes's  Water  and  Public  Health i2mo,  i  50 

Water-filtration  Works i2mo,  2  50 

Gerhard's  Guide  to  Sanitary  House-inspection i6mo,  i  oo 

Sanitation  of  Public  Buildings I2mo,  1  50 

Hazen's  Filtration  of  Public  Water-supplies 8vo,  3  oo 

Leach's  The  Inspection  and  Analysis  of  Food  with  Special  Reference  to  State 

Control , 8vo,  7  50 

Mason's  Water-supply.  (Considered  principally  from  a  Sanitary  Standpoint)  8vo,  4  oo 

Examination  of  Water.     (Chemical  and  Bacteriological.) zarno,  i  25 

*  Merriman's  Elements  of  Sanitary  Engineering Svo^  2  oo 

Ogden's  Sewer  Design i2mo,  2  oo 

Prescott  and  Winslow's  Elements  of  Water  Bacteriology,  with  Special  Refer- 
ence to  Sanitary  Water  Analysis i2mo,  i  25 

*  Price's  Handbook  on  Sanitation i2mo,  i  50 

.Richards's  Cost  of  Food.     A  Study  in  Dietaries i2mo,  i  oo 

Cost  of  Living  as  Modified  by  Sanitary  Science 12010,  i  oo 

Cost  of  Shelter i2mo,  I  oo 

Hichards  and  Woodman's  Air.  Water,  and  Food  from  a  Sanita-y  Stand- 
point  8vo,  2  oo 

*  Richards  and  Williams's  The  Dietary  Computer 8vo,  i  50 

.Rideal's  S  wage  and  Bacterial  Purification  of  Sewage 8vo,  4  oo 

Disinfection  and  the  Preservation  of  Food 8vo,  400 

Turneaure  and  Russell's  Public  Water-supplies 8vo,  5  oo 

Von  Behring's  Suppression  of  Tuberculosis.     (Bolduan.) I2mo,  i  oo 

Whipple's  Microscopy  of  Drinking-water 8vo,  3  50 

Wilson's  Air  Conditioning.    (In  Press.) 

Winton's  Microscopy  of  Vegetable  Foods 8vo,  7  50 

Woodhull's  Notes  on  Military  Hygiene iCmo,  i  50 

*  Personal  Hygiene 12010,  i  oo 


MISCELLANEOUS. 

Association  of   State   and  National  Food  and  Dairy  Departments  (Interstate 
Pure  Food  Commission) : 

Tenth  Annual  Convention  Hell  at  Hartford,  July   17-20,  1906.  ...8va,     3  oo 
Eleventh   Annual    Convention,    Held  at  Jamestown   Tri -Centennial 

Exposition,  July  16-19,  1907.     (In  Press.) 
Emmons's  Geological  Guide-book  of  the  Rocky  Mountain  Excursion  of  the 

International  Congress  of  Geologists Large  Cvo,    i  50 

FerrePs  Popular  Treatise  on  the  Winds 8vo,    4  oo 

Gannett's  Statistical  Abstract  of  the  World   24010.        75 

Gerhard's  The  Modern  Bath  and  Bath-houses.     (In  Press.) 

Haines's  American  Railway  Management I2mo,    2  50 

Ricketts's  History  of  Rensselaer  Polytechnic  Institute,  1824-1804.  .Small  8vo,    3  oo 

Rotherham's  Emphasized  New  Testament Large  8vo,    2  o<> 

Standage's  Decorative  Treatment  of  Wood,  Glass,  Metal,  etc.     (In  Press.) 

The  World's  Columbian  Txposition  of  1893 4to,     i  oo 

Winslow's  Elements  of  Applied  Microscopy I2mo,     i  50 


HEBREW  AND  CHALDEE  TEXT-BOOKS. 

Green's  Elementary  Hebrew  Grammar i2mo,  i  23 

Hebrew  Chrestomathy 8vo,  2  oo 

Gesenius's  Hebrew  and  Chaldee  Lexicon  to  the  Old  Testament  Scriptures. 

(Tregelles.) Small  4to,  half  morocco  5  oo 

Letteris's  Hebrew  Bible 8vo,  2  25 

19 


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